2006 annual review of the literature...emmetropic. myopia was deﬁ ned as minus refraction of at...

$: 2006 ANNUAL REVIEW OF THE LITERATURE...emmetropic. Myopia was deﬁ ned as minus refraction of at least -0.75 D in each meridian. Emmetropia was deﬁ ned as refraction between -0.25$
Volume 38/Number 4/2007 161

2006 ANNUAL REVIEW OF THE LITERATUREMichael T. Cron, OD1

David Goss, OD, PhD2

Dominick Maino, OD, MEd3

1. Michigan College of Optometry, 2. Indiana University School of Optometry3. Illinois College of Optometry

As a service to the membership of the College of Optometrists in Vision Development and readership of Optometry & Vision Development, a review of the literature published in other journals in the preceding year is presented annually. This year’s effort, while attempting to provide the same level of information to the Optometry & Vision Development readership, has a revised format compared to recent annual reviews. The citations are arranged according to topic, but include summaries of the research and descriptions of the papers rather than the previously published abstract verbatim. The reader can use the listed references to fi nd the abstract or the entire article if that is desired.

This will be the fi nal year that the journal will present this annual review. Future issues of Optometry & Vision Development will have articles reviewed and summarized within each issue as opposed to an annual review format.

The articles are chosen by the authors to be representative of those published in the many different journals cited in this review. It is certainly not the authors’ intent that this be exhaustive and comprehensive, but rather representative.

The articles have been placed in the topic area where they appear to principally belong, recognizing certainly that overlap exists. The following outline of this review may prove helpful in perusing or if searching for a particular topic area.

A. AccommodationB. Binocular DysfunctionC. StereopsisD. EsotropiaE. ExotropiaF. StrabismusG. Refractive StatusH. Visual AcuityI. Amblyopia

Correspondence regarding this annual review should be emailed to [email protected] or sent to Dr. Michael Cron, Michigan College of Optome-try at Ferris State University, 1310 Cramer Circle, Big Rapids, MI 49307. All statements are the author’s personal opinion and may not refl ect the opinions of the College of Optometrists in Vision Development, Optometry and Vision Development or any institution or organization to which he may be affi liated. Copyright 2006 College of Optometrists in Vision Development.

Cron MT, Goss D, Maino DM. Annual review of the literature 2006. Optom Vis Dev 2007; (38)4:161-184.

J. Computers/CVS/VDTsK. Eye MovementsL. Vision ScreeningM. Pediatric PathologyN. Exceptional PatientsO. Neuro-optometry/Neurological InsultP. Perceptual ProcessesQ. Reading/Dyslexia

ACCOMMODATIONAccommodation and the relationship to subjective

symptoms with near work for young school children. Sterner B, Gellerstedt M, Sjöström A. Ophthal Physiol Opt 2006;26(2):148-55.

The relationship of nearpoint symptoms to results of amplitude of accommodation and relative accommodation tests was studied. The study subjects were 72 children fi rst examined at ages ranging from 5.8 to 10.0 years, with 59 of those children being examined again 1.8 years later at ages ranging from 7.8 to 11.8 years. Symptoms were determined by an oral questionnaire. Mean differences in amplitude of accommodation by push-up method between those who reported no symptoms and those who reported at least one symptom at the fi rst examination were 2.0 D OD, 2.0 D OS, and 3.1 D OU. At the second examination the differences were 3.6 D OD, 3.4 D OS, and 3.9 D OU. Amplitude of accommodation and negative relative accommodation showed signifi cant relationships to the presence of at least one symptom, but positive relative accommodation did not.

Infl uence of accommodative lag upon the far-gradient measurement of accommodative convergence to accommodation ratio in strabismic patients. Miyata M, Hasebe S, Ohtsuki H. Japan J Ophthalmol 2006;50(5):438-42.

Gradient stimulus and gradient response AC/A ratios were measured using a distance target and -3.00 D add lens in 63 patients with strabismus, ranging in age from 7 to 34 years. The angle of strabismus at distance in the 63 patients ranged from 60 prism diopters of exotropia to 40 prism diopters of esotropia. Accommodative response measurements were taken with a WV-500 autorefractor, an infrared autorefractor with infrared refl ecting mirror in

Optometry and Vision Development162

front of the patient to allow open viewing. Convergence was measured with prism on the alternating cover test. The mean gradient stimulus AC/A ratio was 3.2 prism diopters per diopter (SD=2.7). The mean gradient response AC/A ratio was 5.8 prism diopters per diopter (SD=4.3). The mean accommodative response to the -3.00 D lens at distance was 1.94 D (range, 0.86 to 2.87 D), with patients with myopia tending to show lower accommodative responses. The response AC/A ratio was on average 41% greater than the stimulus AC/A ratio.

Accommodative facility in eyes with and without myopia. Pandian A, Sankaridurg PR, Naduvilath T, O’Leary D, Sweeney DF, Rose K, Mitchell P. Invest Ophthalmol Vis Sci 2006;47(11):4725-31.

Monocular (right eye) accommodative facility at 3 m and 33 cm with semiautomated fl ippers were compared in different refractive groups. The fl ipper lenses were plano/-2.0 D for 3 m and +2/-2 D for 33 cm. The defi nition of emmetropia for the separation into groups was cycloplegic spherical equivalent refractive error ranging from -0.50 to +1.50 D. Mean facility rates at 3 m were 5.5 cpm for myopes (n=20, SD=2.0), 6.9 cpm for emmetropes (n=977, SD=1.7), and 6.9 cpm for hyperopes (n=331, SD=1.7). Rates were signifi cantly lower in myopes than in non-myopes. Mean facility rates at 33 cm were 6.4 cpm for myopes (n=20, SD=1.8), 7.0 cpm for emmetropes (n=977, SD=1.5), and 6.9 cpm for hyperopes (n=331, SD=1.5). Differences between groups were not statistically signifi cant for the near facility.

Accommodative stimulus response curve of emmetropes and myopes. Yeo ACH, Kang KK, Tang W. Ann Acad Med Singapore 2006;35(12):868-74.

Accommodation response measurements were taken for 17 emmetropes and 33 myopes between the ages of 16 and 23 years using a Grand Seiko WR-5100 open view autorefractor. Eleven of the myopes were still progressing into more myopia. Accommodative stimulus was varied in three different ways: by changing distance (targets at 4 m, 1 m, 0.5 m, 0.33 m, and 0.25 m), by plus adds while viewing target at 0.25 m (plus adds of +4, +3, +2, +1, and 0 D), and by minus adds while viewing a target at 4 m (adds of 0, -1, -2, -3, and -4 D). Mean slopes of the accommodative response stimulus curve in diopters of response per diopter of stimulus for the distance change series were 0.80 for the emmetropes, 0.78 for the non-progressing myopes, and 0.80 for the progressing myopes. The mean slopes for the plus add series were 0.27 for the emmetropes, 0.42 for the non-progressing myopes and 0.49 for the progressing myopes. The mean slopes for the minus add series were 0.39 for the emmetropes, 0.29 for the non-progressing myopes and 0.15 for the progressing myopes. Slopes were signifi cantly different with the method of changing

accommodative stimulus but were not signifi cantly different between the three refractive groups. At high accommodative stimulus with the minus add series, progressing myopes tended to have the highest lags of accommodation and emmetropes the lowest, with non-progressing myopes in between.

Ocular motor triad with single vision contact lenses compared to spectacle lenses. Hunt OA, Wolffsohn JS, García-Resúa C. Cont Lens Ant Eye 2006;29(5):239-45.

Thirty subjects with a mean age of 21.0 years had accommodation and vergence measured with infrared automated instruments while viewing targets at accommodative stimulus levels of 0.1, 0.5, 1.0, 2.0, 3.0, 4.0, and 5.0 D. These measurements were taken while wearing full correction for refractive error in spectacles and in contact lenses. Experimental results confi rm theoretical calculations that persons with myopia exert more accommodative effort with contact lenses than with spectacles, and persons with hyperopia exert less accommodative effort with contact lenses than with spectacles. Similarly persons with myopia exert greater vergence effort with contact lenses than with spectacles, and persons with hyperopia less.

Accommodation functions: co-dependency and relationship to refractive error. Allen PM, O’Leary DJ. Vis Res 2006;46(4):491-505.

Various accommodative functions were measured in 64 young adults, ranging in age from 18 to 22 years, over a twelve month period. Thirty of the subjects were classifi ed as being myopic (minus cycloplegic autorefraction of 0.25 D or more). Results of accommodation tests were correlated within groups but not between groups. These groups of tests were accommodative facility, accommodative response, adaptive measures, and amplitude of accommodation. Myopes had signifi cantly lower average amplitude of accommodation, open-loop (pinhole) accommodation, and monocular accommodative facility to a -2.00 D lens at 6 m than non-myopes. Measures showing signifi cant correlations with amount of myopia progression over the twelve months were near (40 cm) monocular accommodative facility (+2/-2) and both monocular and binocular lag of accommodation at 33 cm.

Accommodative lag before and after the onset of myopia. Mutti DO, Mitchell GL, Hayes JR, Jones LA, et al. Invest Ophthalmol Vis Sci 2006;47(3):837-46.

Lag of accommodation was measured under monocular conditions with infrared open-view autorefractors in 568 children who became myopic and 539 children who were emmetropic. Myopia was defi ned as minus refraction of at least -0.75 D in each meridian. Emmetropia was defi ned as refraction between -0.25 and +1.00 D in each meridian. Lag measurements were taken with the


subjects wearing their habitual refractive corrections while they viewed a letter target. Accommodative stimuli were 4 D with a Badal stimulus or with a 25 cm viewing distance and 2 D with a Badal system only. The lag of accommodation was not signifi cantly higher different in the myopia groups in the year of myopia onset on any of the stimulus conditions. However, the lag of accommodation was signifi cantly higher in the myopia group than in the emmetropia group after the onset of myopia. Those differences ranged from 0.13 to 0.56 D in the fi ve years after the onset of myopia. The authors suggested that increased lag of accommodation may be consequence instead of a cause of myopia.

Characteristics of accommodative behavior during sustained reading in emmetropes and myopes. Harb E, Thorn F, Troilo D. Vis Res 2006;46(16):2581-92.

Twenty optometry students, ages 22 to 28 years, with normal binocular vision and stable refractive errors, read from a novel displayed on a computer monitor while accommodative response was measured with an eccentric infrared photorefractor. Nine of the subjects were emmetropic (refractive errors, -0.50 to +0.50 D), and eleven were myopic. Accommodative stimuli of 1.5, 2.5, and 3.5 D were achieved by varying the distance of the computer monitor from the subjects. Subjects with myopia were contact lens full correction of refractive error during testing. The myopia group had a signifi cantly higher lag of accommodation than the emmetropia group. The slope of the accommodative stimulus-response function was not signifi cantly different in the myopia and emmetropia groups, and there was a great deal of intersubject variability in slope. Variability in accommodative response, measured as the mean standard deviation of accommodative response was greater at higher accommodative stimuli, proportional to the magnitude of the accommodative response, and greater in subjects with myopia than in emmetropic subjects. The mean power of accommodative microfl uctuations was signifi cantly greater for higher accommodative stimulus and increased signifi cantly as amount of myopia increased at the 3.5 D accommodative stimulus level. The number of fi xation breaks was greater at the 3.5 D stimulus level than at farther reading distances. The mean number of fi xation breaks in the myopia group was signifi cantly less than in the emmetropia group for accommodative stimuli of 2.5 and 3.5 D. The authors suggested that the small fl uctuations in the accommodative response observed in the myopic subjects could be a blur signal leading to myopia if continued over a long period of time.

Evaluation of accommodative insuffi ciency with the Visual Analogue Scale. Abdi S, Rydberg A, Pansell T, Brautaset R. Strabismus 2006;14(4):199-204.

The Visual Analogue Scale, sometimes also called a Numeric Pain Scale or a Likert scale is a method of

rating subjective severity and relief of pain. Forty-nine children between the ages of 7 and 16 years who had been diagnosed with accommodative insuffi ciency marked a Visual Analogue Scale before and after twelve weeks of wearing individually dispensed reading glasses (average power, +0.75 D) for near work. The scale used was a numerical scale from 0 to 10 on which the subjects were instructed to mark on the continuum line between numbers in response to the question, “If 0 equals no problems when doing near work and 10 equals the worst degree of problems, what number would you grade your problems at near work to be now?” Fifteen emmetropic control subjects with no binocular vision problems or other ocular conditions had a mean scale reading of 0.6 (SD=0.74; range, 0 to 2). The treatment subjects all had scale readings between 6 and 10 before the twelve weeks of treatment. After treatment, 89.8% of the children marked the scale between 0 and 2, and 10.2% reported symptom levels between 3 and 4 on the scale. The reduction in scale reading from before to after treatment was statistically signifi cant (p<0.001).

Accommodation stimulus-response function and retinal image quality. Buehren T, Collins MJ. Vis Res 2006;46(10):1633-45.

Accommodative responses and higher order aberrations were measured with a Complete Ophthalmic Analysis System (COAS) wavefront sensor for accommodative stimuli of 0.17, 1.0, 2.0, 3.0, 4.0, and 5.0 D. Ten subjects, ages 22 to 36 years, had no signifi cant ocular disease, heterophoria within normal limits, anisometropia less than 0.50 D, amplitude of accommodation greater than 5 D, and similar visual acuity in the two eyes. Five of the subjects had myopia (mean refractive error, -2.25 D) and fi ve were emmetropic (mean refractive error, +0.05 D). A beamsplitter allowed measurements to be taken while subjects viewed acuity letter targets. A higher lead of accommodation at far and a higher lag of accommodation at higher accommodative stimulus levels, and thus a lower accommodative stimulus-response function slope, was found under monocular conditions compared to binocular conditions. A shift from positive spherical aberration to negative spherical aberration with increasing accommodation was found as has been reported in several other studies. Leads and lags of accommodation were correlated with spherical aberration metrics, suggesting that accommodative response is, in part, due to effects of spherical aberration.

Dynamic measurement of accommodation and pupil size using the portable Grand Seiko FR-5000 autorefractor. Wolffsohn JS, Ukai K, Gilmartin B. Optom Vis Sci 2006;83(5):306-10.

The video output of a Grand Seiko FR-5000 autorefractor was fed into a computer for comparison to refractive settings on a model eye. The FR-5000


is an infrared open view autorefractor in which an angled infrared refl ecting mirror allows the patient to view objects in real space rather than looking into an instrument. The FR-5000 is a portable version of the table-top Grand Seiko WV-500 autorefractor. The open view aspect of these autorefractors makes it possible to use them for measurements of accommodation. The separation of the measurement bars in the video output showed a high correlation with the refractive error of the model eye. However, measurements were adversely affected by misalignment and inaccuracy in instrument focusing. The results suggest that it can be useful for measurements of accommodation if good eye alignment is achieved.

BINOCULAR DYSFUNCTIONAre orthoptic exercises an effective treatment for

convergence and fusion defi ciencies? Aziz S, Cleary M, Stewart HK, Weir CR. Strabismus 2006;14(4):183-89.

Patient records from the Orthoptic Department of the Tennent Institute of Ophthalmology in Glasgow, United Kingdom over a nine year period were examined. Seventy-eight patients met inclusion criteria of 6/9 visual acuity or better, no prior orthoptic treatment, no strabismus surgery, and no dyslexia. Patients ranged from 5 to 73 years of age, with a mean of 11.9 years. Exophoria was present in 65 cases, esophoria in 11, and orthophoria in one. Nearpoint of convergence was normalized in 47 of 55 patients with initial abnormal fi ndings. Mean near point of convergence improved signifi cantly from 16.6 to 8.4 cm in those 55 cases. Base-out fusional vergence ranges improved at distance and near for patients with exophoria: from 12.5 to 17.5 at distance and from 15.4 to 24.9 at near. Base-in fusional vergence ranges did not improve in the patients with esophoria. Asthenopic symptoms were improved in 65 of the 78 patients.

Effects of orthoptic treatment on the CA/C and AC/A ratios in convergence insuffi ciency. Brautaset RL, Jennings AJM. Invest Ophthalmol Vis Sci 2006;47(7):2876-80.

Stimulus AC/A ratios and CA/C ratios were determined before and after twelve weeks of vision therapy for convergence insuffi ciency. Ten subjects with mean age of 25.4 years participated. AC/A ratios were measured by determining the linear regression slope of Maddox rod and tangent scale phorias as function of accommodative stimulus which was varied by having subjects view a target at 40 cm through -2.00, -1.00, 0, +1.00, and +2.00 D lens adds. CA/C ratios were measured with refractometer measures of accommodation using a difference of Gaussian target viewed at 40 cm through 0 prism and 8 prism diopters base-out. The vision therapy produced statistically signifi cant improvements in near point of convergence,

binocular amplitude of accommodation, and base-out to blur at 40 cm, and a statistically signifi cant reduction in Mallett associated phoria at 40 cm. Mean lag of accommodation changed from 0.10 D to 0.42 D. AC/A ratio (2.04 prism diopters per diopter before therapy and 2.06 after therapy) and CA/C ratio (0.14 diopters per prism diopter before therapy and 0.14 after therapy) were unchanged by vision therapy.

The Mallett fi xation disparity test: infl uence of test instructions and relationship with symptoms. Karania R, Evans BJW. Ophthal Physiol Opt 2006;26(5):507-22.

A survey of practitioners who use the Mallett associated phoria (or aligning prism) test found that the usual instructions are to ask if marker lines are aligned or not without regard to whether the lines are moving. A study of 105 patients, 7 to 70 years of age, was performed to compare results obtained with those standard instructions and modifi ed instructions with additional questions about whether the lines are moving. In the latter case, prism was added until the lines did not move. On near testing, the additional questioning resulted in more cases of non-zero fi xation disparity and a better correlation of test results with symptoms. The results suggest that patients should be asked not only whether the nonius lines are aligned but also whether either line ever appears to move.

Normal values of distance heterophoria and fusional vergence ranges and effects of age. Álvarez CP, Puell MC, Sánchez-Ramos MC, Villena C. Graefe’s Archive for Clinical and Experimental Ophthalmol 2006;244(7):821-24.

Distance von Graefe phoria measurements and distance phoropter rotary prism vergence ranges were taken in 271 non-clinical subjects. The subjects were stratifi ed into six age categories: 21 to 30 years (n=57), 31 to 40 years (n=52), 41 to 50 (n=48), 51 to 60 (n=44), 61 to 70 (n=43) and over 70 (n=27). Mean distance phorias ranged from 0.3 to 0.6 prism diopters exo (SDs ranging from 1.8 to 3.1) in the age groups from 21 to 70 years. The mean phoria in the over 70 group was 0.2 prism diopters eso. There was no signifi cant effect of age on distance phoria, nor was there an effect of age on distance base-in break or base-out break. The average base-in break values were between 8.6 and 9.6 prism diopters in the six age groups, with SDs ranging from 2.0 to 3.1. The mean base-out break fi ndings ranged from 16.7 to 20.3 prism diopters, with SDs from 7.3 to 9.0. Statistically signifi cant changes with age were found in the base-in recovery (p=0.00001) and in the base-out recovery (p=0.0005). The mean base-in recovery decreased from 5.2 prism diopters (SD=2.2) at 21 to 30 years of age to 2.7 prism diopters (SD=2.1) for subjects over 70. The mean base-out recovery decreased from 8.2 prism diopters (SD=5.4) at 21 to 30 years of age to


4.9 prism diopters (SD=7.6) for subjects over 70. Linear regression equations fi tted to the recovery data as a function of age showed a decline in the base-in recovery of about 0.05 prism diopters per year and a decline in the base-out recovery of about 0.07 prism diopters per year.

Effect of heterophoria measurement technique on the clinical accommodative convergence to accommodation ratio. Escalante JB, Rosenfi eld M. Optom 2006;77(5):229-34.

Sixty subjects between the ages of 20 and 25 years were tested at 40 cm with the von Graefe, Maddox rod, and modifi ed Thorington dissociated phoria methods. Phoria measurements were taken through the distance refractive correction and through +1.00 D and -1.00 D adds to determine stimulus gradient AC/A ratios. The mean values of the AC/A ratios in prism diopters per diopter were 3.47 with the von Graefe method, 2.99 with the Maddox rod procedure, and 2.46 with modifi ed Thorington testing. The differences were statistically signifi cant. The most repeatable AC/A ratios when retested after at least 24 hours were those determined with the modifi ed Thorington test.

Comparison of subjective heterophoria testing with a phoropter and trial frame. Casillas Casillas E, Rosenfi eld M. Optom Vis Sci 2006;83(4):237-41.

Sixty subjects between the ages of 20 and 34 years were tested at 6 m and at 40 cm with three different dissociated phoria procedures on two occasions at least 24 hours apart. The three testing procedures were the Graefe test, Maddox rod test, and modifi ed Thorington test. Each of the three tests was performed both with a phoropter and with a trial frame. All three testing methods showed better repeatability in a trial frame than in the phoropter at both distance and near for lateral phoria testing. For vertical phorias, some testing conditions showed better repeatability with the phoropter and some with the trial frame.

Accommodative insuffi ciency is the primary source of symptoms in children diagnosed with convergence insuffi ciency. Marran LF, DeLand PN, Nguyen AL. Optom Vis Sci 2006;83(5):281-89.

After examination of 299 California school children (grades 4, 5 and 6), 170 were classifi ed into one of the following categories: normal binocular vision (NBV; n=102), convergence insuffi ciency only (CI; n=44), accommodative insuffi ciency only (AI; n=14), convergence insuffi ciency with accommodative insuffi ciency (CIwAI; n=10). The 44 children with convergence insuffi ciency had (a) near exophoria greater than far exophoria by at least four prism diopters and (b) failure to meet Sheard’s criterion, near positive fusional vergence break less than or equal to 15, and/or a near point of convergence greater than or equal to 6 cm. Accommodative insuffi ciency was defi ned as

monocular push-up amplitude of accommodation at least 2 D below Hofstetter’s age-based norm for minimum expected amplitude of accommodation, 15-(0.25)(age). A survey with 15 questions asking about the frequency of symptoms was administered to the subjects. The NPC was most receded in the CIwAI group. The NPC averages were: NBV, 2.0 cm (SD=2.1); CI, 6.2 (SD=4.1); AI, 6.0 (SD=6.1); CIwAI, 13.3 (SD=9.4). The base-in and base-out breaks and recoveries at 40 cm were all 3 to 4 prism diopters lower on average in the CIwAI group than in the CI group. The base-in breaks and recoveries were lower by about 3 to 4 prism diopters and the base-out breaks and recoveries were higher by about 3 to 4 prism diopters in the AI group compared to the CI group. The average symptom scores were: NBV, 10.3 (SD=8.2); CI, 12.9 (SD=10.6); AI, 19.7 (SD=12.7); CIwAI, 22.8 (SD=12.7). The effect of AI on symptom score was statistically signifi cant (p<0.001), but the effect of CI was not (p=0.16). The symptom score was signifi cantly higher in CIwAI than in CI (p=0.003). Because the children in the CI group were not signifi cantly more symptomatic than the normal binocular vision group, the authors suggested that symptoms in many cases diagnosed as CI may be due to a co-existing AI.

Measurements of objective and subjective fi xation disparity with and without a central fusion lock. Brautaset RL, Jennings JAM. Med Sci Monitor 2006;12(2):MT1-4.

Subjective measurements of fi xation disparity with and without a central fusion lock were compared to objective measures of fi xation disparity. The subjective measurements were made with the Sheedy distance Disparometer. Objective measurements were made with the scleral search coil technique. Five persons with a mean age of 23.5 years served as subjects. The central fusion lock was an OXO target which was centered in the middle of the nonius lines when set for zero fi xation disparity. Without the central fusion lock, subjective and objective fi xation disparities were signifi cantly different. With the central fusion lock, subjective and objective fi xation disparities were not signifi cantly different. The sizes of both the subjective fi xation disparity and the objective fi xation disparity were smaller with the central fusion lock than without it. The inclusion of central fusion lock makes subjectively determined fi xation disparity closer to the objective fi xation disparity.

Double-masked randomized placebo-controlled trial of the effect of prismatic corrections on rate of reading and the relationship with symptoms. O’Leary CI, Evans BJW. Ophthal Physiol Opt 2006;26(6):555-65.

The effect of prism correction on reading was studied using the Wilkins Rate of Reading Test. Eighty subjects all manifested an associated phoria on the near Mallett Unit. There were 58 subjects with exophoria (mean


age, 43 years), 15 subjects with esophoria (mean age 16 years), and seven subjects with vertical phoria (mean age, 61 years). The performance of subjects on the reading test was determined with a prism power equal to that measured with the near Mallett Unit and with a control lens with zero prism power. For subjects with exophoria and an associated phoria of two prism diopters or greater, reading performance was signifi cantly better with the prism. Improvement in performance was not related to level of initial symptoms. The difference in reading performance with and without prism was not signifi cant in the esophoria and vertical phoria groups.

Citation patterns in the optometric and ophthalmologic clinical binocular vision literature. Goss DA. Optometry and Vision Sci 2006;83(12):895-902.

Citation analyses were performed on two current clinical binocular vision books from optometry and two from ophthalmology, as well as on articles published in the fi ve years from 2000 to 2004 in optometry and ophthalmology journals. Topical parameters used to choose source books and articles limited the analysis to topics in which both professions would have the same testing and treatment options within their scopes of practice, that is, nonstrabismic binocular vision disorders, diagnosis and management of nonpresbyopic accommodative disorders, and testing procedures for those conditions. Both optometry and ophthalmology more frequently cited literature originating from their own profession. The journals with the highest numbers of citations totaled from all sources on the chosen topics were Optometry and Vision Science, Ophthalmic and Physiological Optics, American Journal of Ophthalmology, Investigative Ophthalmology and Visual Science, and Optometry (Journal of the American Optometric Association). This article provides objective evidence of bias in citation patterns.

Orthoptic indications for contact lens wear. Evans BJW. Cont Lens Ant Eye 2006;29(4):175-81.

Indications for the use of contact lenses in binocular vision anomalies are discussed. Contact lenses are the preferred optical correction for anisometropia. Three illustrative cases of contact lens wear in anisometropia are presented. Contact lenses can also be used in cases where refractive correction helps to solve a binocular vision problem, such as in accommodative esotropia. A case is presented in which toric prism contact lenses were prescribed in esophoria. Other less common potential uses of contact lenses are for occlusion in patching for amblyopia or in congenital nystagmus to reduce nystagmus amplitude.

Subtle binocular vision anomalies in migraine. Harle DE, Evans BJW. Ophthal Physiol Opt 2006;26(6):587-96.

Results of standard clinical of binocular vision tests were compared in 25 persons with migraine (mean age, 37.5 years) and 25 control subjects (mean age, 36.8 years). The tests used were cover test, associated phoria, Randot stereopsis, Maddox rod, Maddox wing, near point of convergence, vergence facility with prism fl ippers, and fusional vergence ranges. Signifi cantly more persons with migraine showed a heterophoria at 6 m with the Maddox rod, but not at near and not with either cover test or Maddox wing at either 6 m or near. Signifi cantly more persons with migraine showed a fi xation disparity at either 6 m or near, but the amount of the Mallett aligning prism (associated phoria) was not signifi cantly different in the two groups. On the Randot shapes test, stereopsis was not signifi cantly different in the two groups, but it was different by the Randot circles test. Near point of convergence, vergence facility, and fusional vergence ranges were not signifi cantly different in the two groups. The results suggest that any differences in migraine tend to be subtle and binocular vision treatments should not be initiated solely based on the presence of migraine.

STEREOPSISReal depth vs Randot stereotests. Leske DA, Birch

EE, Holmes JM. Am J Ophthalmol 2006;142(4):699-701.

Performance on four different stereotests was tested in 182 patients with strabismus, ages 4 to 84 years. Two of the tests were real depth tests and two tests were Randot tests. At distance, fi ner disparities were appreciated with the Frisby-Davis 2 distance stereotest than with the Distance Randot test. At near, fi ner disparities were appreciated with the Near Frisby test than with the Preschool Randot. The authors suggested that the Randot tests would be more appropriate for detecting subtle changes in stereoacuity, while the Frisby-Davis 2 and Near Frisby real depth tests would be better for fi nding whether stereopsis is present or not and for fi nding the best measurable stereopsis.

Assessment of a new distance Randot stereoacuity test. Fu VLN, Birch EE, Holmes JM. J AAPOS 2006;10(5):419-23.

Three stereopsis tests were performed on 23 normal children, ages 4 to 14 years; 21 normal adults, ages 20 to 36 years; and 131 patients with strabismus, ages 4 to 85 years. The tests were distance Randot, distance Frisby-Davis 2, and near Preschool Randot. The new distance Randot test yielded results similar to published normative results from other stereoacuity tests. In cases where distance Randot results differed from the near Preschool Randot test, poorer stereoacuity was usually


found on the distance Randot test. In cases where distance Randot results differed from the Distance Frisby-Davis 2, poorer stereoacuity was usually found on the distance Randot test. The authors concluded that the distance Randot may be more likely to fi nd anomalies in distance stereopsis that the other two tests.

Effect of age on adult stereoacuity as measured by different types of stereotest. Garnham L, Sloper JJ. Br J Ophthalmol 2006;90(1):91-95.

Stereoacuity was measured in sixty subjects, ages 17 to 83 years, on four different stereo tests: TNO, Titmus, Frisby near, and Frisby-Davis distance test. Stereoacuity decreased with age with all tests, with the Spearman rank correlation coeffi cient being statistically signifi cant (p<0.001). Stereoacuity measured with the TNO test was signifi cantly different from that found with each of the other tests. The median values obtained on the four tests were: TNO, 60 seconds of arc; Titmus, 40 seconds; Frisby near, 30 seconds; Frisby-Davis, 15 seconds. None of the subjects reported diffi culty with judgments of distance in everyday tasks such as pouring a drink into a cup. Fusional vergence ranges and near point of convergence were also measured. Near point of convergence, base in range at distance, base in range at near, and base out range for near did not show signifi cant correlations with age. Base out range at distance did show a signifi cant correlation with age (p<0.05), with it averaging just a few prism diopters less for 70 to 83 year olds than for 17 to 29 year olds.

Stereopsis in refractive surgery. Kirwan C, O’Keefe M. Am J Ophthalmol 2006;142(2):218-22.

Eighty-three patients, ages 19 to 56 years, who underwent either LASIK (124 eyes) or LASEK (14 eyes) had stereopsis measured before refractive surgery and again one week or three weeks after surgery using a red-green anaglyph stereo test. Additional stereopsis determinations were made six weeks and twelve weeks after surgery in unilaterally treated patients and after treatment of the second eye in bilaterally treated patients. Fifty-fi ve of the patients had bilateral sequential treatment and 28 patients had unilateral surgery. Thirty-two (38.6%) of the patients retained fi ne stereopsis after the operation of one eye. Loss of stereopsis after treatment of one eye was correlated with the amount of anisometropia present after the operation. All patients who underwent bilateral treatment regained pre-operative stereopsis after surgery on the second eye.

Random Dot E stereotest: testability and reliability in 3- to 5-year-old children. Vision in Preschoolers Study Group. J AAPOS 2006;10(6):507-14.

Three to fi ve year old children enrolled in Head Start in one of fi ve cities across the United States were subjects in this study. Stereotesting with the Random Dot E test was attempted on two occasions on 1,257 children.

Pretesting was performed at 50 cm with a card with no stereo target being compared to a card with a raised three dimensional E to determine testability. Children who responded correctly four of four or four of fi ve times were considered testable. Stereotesting was performed at distances of 50, 100, and 150 cm, which correspond to 504, 252, and 168 arc seconds, respectively. At the fi rst session, testability was found in 86% of three year olds, 89% of four year olds, and 93% of fi ve year olds, a signifi cant increase with age (p<0.02). At the second session, testability was established in 90% of three year olds, 94% of four year olds, and 98% of fi ve year olds, also a signifi cant increase with age (p=0.0001). Test-retest agreement did not change with age.

ESOTROPIALong-term motor and sensory outcomes after

early surgery for infantile esotropia. Birch EE, Stager DR Sr. J AAPOS. 2006 Oct;10(5):409-13. J AAPOS. 2006 Oct;10(5):409-13.

This article discusses the timing of esotropia surgery and the dilemma that early surgery may yield better sensory outcomes whereas later surgery may result in better alignment. They report the results of 50 consecutive children enrolled in a prospective study who had surgery by 6 months of age and were followed for 4-17 years. Results from this early surgery group were compared with a concurrently recruited cohort who had surgery at 7-12 months (n=78). Both groups had similar postoperative alignment and had similar rates of additional surgery. However, more children in the early-surgery group had peripheral fusion (p < 0.02), central fusion (p< 0.01), Randot stereopsis (< 0.003), and Randot stereoacuity of 200 seconds or better (20% vs 9%; p < 0.05). They concluded that earlier surgery resulted in better fusional outcomes without a loss of alignment.

Maximum motor fusion combined with one-hour preoperative prism adaptation test in patients with acquired esotropia. Ela-Dalman N, Velez G, Thacker N, Britt MT, Velez FG. J AAPOS. 2006 Dec;10(6):561-64.

This was a retrospective study of acquired esotropes without amblyopia, previous surgery or oblique muscle problems who underwent bilateral medial rectus muscle recessions based on the distance angle of deviation measured with the maximum motor fusion test followed by prism adaptation test. Alternate prism and cover testing was performed after 1 hour of prism adaptation to determine the angle of deviation for surgical correction. They found that by combining the maximum motor fusion and preoperative prism adaptation it afforded increased amounts of medial rectus muscle recession and decreased the risk of postoperative undercorrection without increasing the risk of overcorrection.


Strabismus surgery for elimination of bifocals in accommodative esotropia. Lueder GT, Norman AA. Am J Ophthalmol 2006 Oct;142(4):632-35.

Sixteen patients with high AC/A rations who wore bifocals to treat their accommodative esotropia underwent strabismus surgery. The surgery was planned based on the results of the prism adaptation test (PAT) for near esotropia without the bifocals. All patients reportedly had successful outcomes after one or two surgeries. Three of 13 (23%) patients with positive PATs required two surgeries and two of three (67%) patients with negative PATs required two surgeries. Binocularity remained the same in 13 patients and improved in three patients. Glasses were eliminated entirely in half of the patients.

Age-related distance esotropia. Mittelman D. J AAPOS. 2006 Jun;10(3):212-13.

This was a descriptive study dealing with a form of acquired esotropia occurring in older adults, which the author termed age-related distance esotropia. A retrospective consecutive case review of 26 patients with this condition was performed. These patients ranged in age from 62 to 91 years old with a median age of 77 years. They were from 4 prism diopters (PD) esotropic to 20 PD at distance and from 9 PD esotropic to 10 PD exophoric at near. None of these patients had an obvious underlying neurologic disorder, such as tumor or stroke. Treatment was prescribing the minimum prismatic correction that eliminated distance diplopia. The author reported that this treatment successfully eliminated the symptoms in all patients and none of them required surgery. The author described this distinctive form of strabismus that occurs in older adults that is characterized by esotropia greater at distance than near. The etiology of this disorder is unknown, but it is hypothetically secondary to anatomical changes in the orbit and/or muscles associated with aging.

Longitudinal changes in the spherical equivalent refractive error of children. with accommodative esotropia. Lambert SR, Lynn MJ. Br J Ophthalmol 2006 Mar;90(3):357-61.

Children with accommodative esotropia had their spherical equivalent refractive error monitored for a mean of 4.4 years. The authors divided the 126 subjects into three groups based on their age at the time they received their fi rst spectacle prescription. The refraction was greatest in the youngest group. All groups had an initial increase in spherical equivalent refraction followed later by a decrease. The greatest decrease was found in the oldest age group. The authors concluded that longitudinal changes in spherical equivalent refraction for children with accommodative esotropia vary as a function of their age when spectacle wear is initiated.

EXOTROPIATiming of surgery for primary exotropia in

children. Asjes-Tydeman WL, Groenewoud H, van der Wilt GJ. Strabismus 2006 Dec;14(4):191-97.

This retrospective study of 60 consecutive patients compared alignment and sensory functions after surgery in children with primary exotropia who had their surgery at ages less than 7 years with those who had surgery after age 7. Children who had surgery before the age of seven had signifi cantly better alignment and sensory functions (p = 0.002). Also, the younger group had signifi cantly fewer reoperations. The authors concluded that the outcomes were better in patients whose surgical intervention for primary exotropia was before age 7.

The long-term result of slanted medial rectus resection in exotropia of the convergence insuffi ciency type. Choi MY, Hwang JM. Eye. 2006 Nov;20(11):1279-83.

This study looked at postsurgical outcomes of a slanted medial rectus (MR) resection technique for intermittent exotropia (X(T)) of the convergence insuffi ciency type. In all, 10 patients with an X(T) greater at near than at distance by 10 prism diopters (PD) or more were included in this prospective study. At the fi nal follow-up examination, all patients demonstrated an exodeviation of 10 PD or more at distance and near, and the exodeviation difference between distance and near deviation was within 10 PD in fi ve of the 10 patients. The authors concluded that bilateral slanted MR resections in patients with X(T) of the convergence insuffi ciency type resulted in undercorrection in all patients.

STRABISMUSFactors associated with childhood strabismus:

fi ndings from a population-based study. Robaei D, Rose KA, Kifl ey A, Cosstick M, Ip JM, Mitchell P. Ophthalmol 2006 Jul;113(7):1146-53.

The authors aimed to describe through a population- based cross-sectional study the strabismus prevalence and associated factors in a representative sample of 6-year-old Australian children. They included 1,739 children from Sydney. Cover testing was performed at near and distance fi xation and strabismus was defi ned as any heterotropia at near or distance fi xation, or both, on cover testing. Strabismus was seen in 2.8% of the population; 54% had esotropia, 29% had exotropia, 15% had microstrabismus, and 1 child had VIth cranial nerve palsy. Prematurity was associated with a 5-fold increase in the risk of esotropia. The presence of strabismus was signifi cantly associated with hyperopia, astigmatism, anisometropia, and amblyopia (P<0.0001).


Prevalence and development of strabismus in 10-year-old premature children: a population-based study. Holmström G, Rydberg A, Larsson E. J Pediatr Ophthalmol Strabismus 2006 Nov-Dec;43(6):346-52.

The authors looked at the prevalence and development of strabismus, at 10 years, in children born prematurely. Their study included 216 premature and 217 full-term children from the same geographic area. They found strabismus in 16.2% of the premature children and only 3.2% of the full-term children. They found some signifi cant risk factors for strabismus at age 10, including anisometropia at 6 months and spherical equivalent refractive errors (i.e., >+3 D or < -3 D) at 2.5 years. The conclusion was that children born prematurely have a greater risk of strabismus at age 10 than children born at term.

The cost utility of strabismus surgery in adults. Beauchamp CL, Beauchamp GR, Stager DR Sr, Brown MM, Brown GC, Felius J. J AAPOS. 2006 Oct;10(5):394-99.

Cost-utility analysis is a methodology that evaluates the cost of medical care in relation to the gain in a measure referred to as quality-adjusted life years (QALYs). The authors set out to develop a cost model for surgical care for adult strabismus. Interviews were conducted with adult patients before and after strabismus surgery. Their cost model resulted in an estimated total cost of 4,254 dollars per case, and a signifi cant improvement of utility was found. Their calculations resulted in a cost-utility for strabismus surgery on adults of 1,632 dollars/QALY. In the United States, treatments <50,000 dollars/QALY are generally considered “very cost-effective.” Strabismus surgery in adults falls well within this range.

Prevalence of eye disorders in young children with eyestrain complaints. Ip JM, Robaei D, Rochtchina E, Mitchell P. Am J Ophthalmol 2006 Sep;142(3):495-97.

This study attempted to determine whether eyestrain symptoms predict eye conditions in 6-year-old children. Parental questionnaires and eye exams were conducted on 1740 children. Most children (82.3%) had a normal eye examination, while refractive errors, amblyopia, and strabismus were found in 15.0%, 3.6%, and 7.3%, respectively. Most children complaining of eyestrain had a normal eye examination; whereas most children with refractive error, amblyopia, or strabismus were free of eyestrain. They concluded that this complaint was a poor marker of eye conditions in young children.

REFRACTIVE STATUSA cohort study of incident myopia in Singaporean

children. Saw SM, Shankar A, Tan SB, Taylor H, Tan DTH, Stone RA, Wong TY. Invest Ophthalmol Vis Sci 2006;47(5):1839-44.

Singaporean Chinese children, ages 7 to 9 years, without myopia were followed over a three year period. Myopia was defi ned as a minus spherical equivalent of at least 0.75 D on cycloplegic autorefraction. A total of 994 children participated in the study. When results were controlled for age, gender, parental income, books read per week, and intelligence quotient (IQ), relative risk of developing myopia was 1.55 for two myopic parents versus no myopic parents. The relative risk for incidence of myopia was 1.50 for IQ in the third tertile versus IQ in the fi rst tertile. Reading as measured by books read per week was not signifi cantly associated with the incidence of myopia.

The possible effect of undercorrection on myopic progression in children. Adler D, Millodot M. Clin Exp Optom 2006;89(5):315-21.

Forty-eight children with myopia, ages six to fi fteen years, were followed for 18 months after being randomly assigned to a full correction group (n=23) or a 0.50 D undercorrection group (n=25). Mean ages of the subjects were 10.24 years (SD=2.18) in the full correction group and 9.93 (SD=2.66) years in the undercorrection group. Mean beginning refractive errors were -2.82 D (SD=1.06) in the full correction group and -2.95 D (SD=1.25) in the undercorrection group. Mean changes in myopia over the 18 month period were -0.82 D (SE=0.10) in the full correction group and -0.99 D (SE=0.09) in the undercorrection group. The difference in amount of myopia progression was not statistically signifi cant at the 0.05 level by the Mann-Whitney test. The amounts by which myopia progression was greater in the undercorrection group than in the full correction group in different classifi cations of subjects were: females, 0.20 D; males, 0.10 D; less than 3 D of myopia, 0.13 D; 3 D of myopia or more, 0.19 D; esophoria at near, 0.19 D; orthophoria or exophoria at near, 0.13 D. None of those differences were statistically signifi cant. The authors suggested that undercorrection was not an effective method of slowing myopia progression in children.

Astigmatism and its components in 6-year-old children. Huynh SC, Kifl ey A, Rose KA, Morgan I, et al. Invest Ophthalmol Vis Sci 2006;47(1):55-64.

Refractive astigmatism and corneal astigmatism measurements were obtained for 1,765 children, ages 6 to 7 years, in Sydney, Australia. Refractive astigmatism was determined using cycloplegic autorefraction. Corneal astigmatism was calculated by converting keratometer readings into corneal powers using a refractive index of 1.3375. The prevalence of


refractive astigmatism of 1.00 D or greater was 4.8%. The prevalence of corneal astigmatism of 1.00 D or greater was 27.7%. The prevalence and mean amounts of both refractive and corneal astigmatism were greater in East Asian and South Asian children than in European Caucasian children. Refractive and corneal astigmatism both averaged higher in children with higher amounts of myopia and hyperopia.

Prevalence and associations of anisometropia and aniso-astigmatism in a population based sample of 6 year old children. Huynh SC, Wang XY, Ip J, Robaei D, et al. Br JOphthalmol 2006;90(5):597-601.

Cycloplegic autorefraction, keratometry, ultrasonography, and questionnaire data were analyzed for 1,724 children with an average age of 6.7 years in Sydney, Australia. Mean spherical equivalents were +1.26 D in the right eye and +1.31 D in the left eye. The prevalence of anisometropia, defi ned as a difference in spherical equivalents between the two eyes of at least 1.0 D, was 1.6%. The prevalence of aniso-astigmatism, defi ned as a difference in astigmatism between the two eyes of at least 1.0 D, was 1.0%. Both anisometropia and aniso-astigmatism were more common in hyperopia of 2.0 D or more than in hyperopia of less than 2.0 D. The prevalence of anisometropia was greater in children with myopia than in children with hyperopia. Signifi cant associations with anisometropia were found with amblyopia, exotropia, and neonatal intensive care unit admission. Signifi cant associations with aniso-astigmatism were found with amblyopia, maternal age greater than 35 years, and neonatal intensive care unit admission. Interocular differences in axial length and anterior chamber depth were found in anisometropia. Interocular differences in corneal astigmatism were found in aniso-astigmatism.

Longitudinal study of anisometropia in Singaporean school children. Tong L, Chan YH, Gazzard G, Tan D, et al. Invest OphthalmolVisSci2006;47(8):3247-52.

Singaporean children, ages 7 to 9 years, underwent annual cycloplegic autorefraction and ultrasonography over a three year period. Anisometropia was defi ned as a difference in spherical equivalent refractive error of at least 1.00 D between the two eyes. Of 1,979 children in the study, 71 (3.6%) had anisometropia at the beginning of the study. An incidence of anisometropia during the three years of the study occurred in 144 (7.55%) children. The mean intereye difference in spherical equivalent refractive error was 0.29 D (SD=0.46) at the beginning of the study and 0.44 D (SD=0.59) after three years. The change in the difference in spherical equivalent refractive error between the two eyes was correlated with the change in the difference in axial length between the two eyes (r=0.43).

The sclera and myopia. Rada JAS, Shelton S, Norton TT. Exp Eye Res 2006;82(2):185-200.

This paper reviews an extensive literature on scleral development, biochemistry, and changes found in laboratory studies of myopia. The sclera is composed of collagen fi brils in irregularly arranged lamellae, along with proteoglycans and glycoproteins. Scleral fi broblasts, which synthesize extracellular matrix, are found between the lamellae of the sclera. The sclera is a dynamic tissue in which the composition of the extracellular matrix can be altered and scleral remodeling can occur due to changes in visual input. Such remodeling is thought to be regulated by particular biochemical growth factors. The scleral thinning in high myopia appears to be a consequence of this scleral remodeling.

Prevention of myopia progression with 0.05% atropine solution. Lee JJ, Fang PC, Yang IH, Chen CH, et al. J Ocular Pharmacol Therap 2006;22(1):41-46.

Fifty-seven children, ages 6 to 12 years, who had initial spherical refractive error of -0.50 to -5.50 D participated in the study. Twenty-one children (12 boys and 9 girls) had one drop of 0.05% atropine instilled each evening (average initial age, 8.38 years). Thirty-six children (18 boys and 18 girls) served as a control group (average initial age, 8.11 years). The mean spherical equivalent refractive error in the treatment group was -1.58 D at the beginning of the study and -1.97 D at the end of the study. The treatment group was followed for an average of 19.9 months for an average rate of myopia progression of -0.28 D/yr. The mean spherical equivalent refractive error in the control group was -1.41 D at the beginning of the study and -2.76 D at the end of the study. The treatment group was followed for an average of 21.5 months for an average rate of myopia progression of -0.75 D/yr. The rate of progression was signifi cantly lower in the treatment group than in the control group (p<0.001).

Atropine for the treatment of childhood myopia. Chua WH, Balakrishnan V, Chan YH, Tong L, et al. Ophthalmol 2006;113(12):2285-91.

Six to twelve year old children participated in a study in which the treatment group subjects had unilateral instillation of 1% atropine once each night and control subjects had unilateral instillation of a placebo drop once each night. Three hundred forty-six subjects completed the two year study. Refractive errors were measured by cycloplegic autorefraction. At the end of two years, the average refractive change in the placebo treated eyes was -1.20 D (SD=0.69) and the average change in axial length was +0.38 mm (SD=0.38). The average change in two years in refractive error in the atropine treated eyes was -0.28 D (SD=0.92) with an average change in axial length of -0.02 (SD=0.35). The refractive changes in the atropine treated eyes and the placebo treated eyes were signifi cantly different. The changes in the untreated eyes


in both the atropine group and the placebo group were similar to the changes in the eyes treated with placebo drops.

The Nepal longitudinal study: biometric characteristics of developing eyes. Garner LF, Stewart AW, Owens H, Kinnear RF, et al. Optom Vis Sci2006;83(5):274-80.

Cycloplegic autorefraction, A-scan ultrasonography, and videophakometry measurements were taken over an eight year period on the left eyes of 895 Tibetan children, ages 6 to 18 years. Subjects were classifi ed as being myopic if the spherical equivalent refractive error showed more than 0.50 D of myopia. All other subjects were classifi ed as nonmyopic. Differences between the myopia and nonmyopia groups in the rates of change in the biometric characteristics of the eye were as follows: decrease in anterior chamber depth, 0.012 mm/yr greater in myopia group; increase in vitreous depth, 0.084 mm/yr greater in myopia group; increase in anterior crystalline lens radius, 0.073 mm/yr greater in myopia group; increase in posterior crystalline lens radius, 0.017 mm/yr greater in myopia group; decrease in crystalline lens thickness, 0.005 mm/yr greater in myopia group; and decrease in crystalline lens power, 0.059 D/yr greater in myopia group. The rate of change in corneal radius was equivalent in the myopia and nonmyopia groups, but the cornea was steeper by 0.09 mm in the myopia group than in the nonmyopia group at all ages (p<0.001).

Depth-of-focus of the human eye: theory and clinical implications. Wang B, Ciuffreda KJ. SurvOphthalmol 2006;51(1):75-85.

This review paper examines the factors which affect the depth of focus of the human eye and the implications of depth of focus for clinical measurements and clinical care. Factors external to the individual which affect depth of focus are luminance, contrast, spatial frequency, detail, and wavelength of the visual target and test environment. Internal factors affecting depth of focus are visual acuity, pupil size, retinal eccentricity, refractive state, and age. Depth of focus can affect results of clinical tests which require judgments of clarity and blur. Examples include subjective refraction, amplitude of accommodation, and relative accommodation. Depth of focus affects lag or lead of accommodation. Depth of focus is often a factor in ophthalmic lens design, but its potential effects in refractive surgery haven’t been fully examined. Depth of focus can be adversely affected by various retinal and cortical conditions, such as amblyopia or macular degeneration.

Objective blur thresholds in free space for different refractive groups. Vasudevan B, Ciuffreda KJ, Wang B. Curr Eye Res 2006;31(2):111-18.

Objective depth of focus was measured in 35 young adults, ages 20 to 35 years, using a Power Refractor II

automated refractor. Mean depth of focus in 16 myopes was 0.61 D (SD=0.07), compared to 0.53 D (SD=0.09) in 13 emmetropes and 0.55 D (SD=0.01) in 6 hyperopes. The greater depth of focus found in myopes is consistent with studies which have subjectively greater depth of focus in myopes. These results appear to support theories suggesting that greater amounts of retinal image defocus over time plays a role in myopia development.

Retinal image quality, reading and myopia. Collins MJ, Buehren T, Iskander DR. Vis Res 2006;46(1-2):196-215.

A Complete Ophthalmic Analysis System (COAS) Hartmann-Shack wavefront sensor was used to study modulation transfer functions, higher order aberrations, and retinal image quality in 40 adult subjects. Twenty of the subjects were myopic with spherical equivalent refractive errors ranging from -1.00 to -7.50 D and ages ranging from 19 to 24 years. These subjects were continuing to progress into myopia, averaging a change of -0.73 D over the last two years. Another group of 20 subjects was emmetropic, with spherical equivalent refractive errors of -0.25 to +0.25 D and ages of 19 to 28 years. All subjects wore best sphere and cylinder correction during testing. Testing was done with fi xation at 5.5 m and at the subjects’ habitual reading distance before and after reading a novel for two hours. The myopia group had mean leads of accommodation for far of 0.23 D before reading and 0.31 D after reading, and had mean lags of accommodation of 0.72 D before reading and 0.60 D after reading. The emmetropia group had mean leads of accommodation for far of 0.09 D before reading and 0.15 D after reading, and had mean lags of accommodation of 0.50 D before reading and 0.47 D after reading. A consistent fi nding of poorer retinal image quality for near than for far was observed in both groups before reading. Retinal image quality at far declined after reading and often was slightly better for near than for far after reading. Calculated depth of focus was greater in the myopia group than in the emmetropia group. Analyses of the relationship between various metrics of image quality and the lead or lag of accommodation tended to show moderate correlations, suggesting that accommodative response is affected in part by the infl uence of higher order aberrations on retinal image quality.

Objective real-time measurement of instrument myopia in microscopists under different viewing conditions. Ting PWK, Schmid KL, Lam CSY, Edwards MH. Vis Res 2006;46(15):2354-62.

Instrument myopia was measured with an infrared photorefractor during microscopy work in 20 inexperienced microscopists (age range, 21 to 30 years; mean age, 24.1 years) and 10 experienced microscopists (age range, 26 to 34 years; mean age, 31.2 years). The average microscopy work experience in the experienced


subjects was 4.8 years. Beamsplitters were used to take photorefractor measurements during the microscopy tasks. Measurements were taken under different viewing conditions and different microscope settings by changing whether spectacle correction was used, and varying target quality, eyepiece power, magnifi cation, and illumination of the target. The mean instrument myopia in inexperienced subjects was 1.98 D (SD=0.91) compared to 1.38 D (SD=0.75) in experienced subjects. The difference between inexperienced and experienced microscopists was statistically signifi cant (p=0.028). The level of instrument myopia did not change signifi cantly with changes in viewing conditions or microscope settings.

Corneal optics after reading, microscopy, and computer work. Acta Ophthalmol (Scand) 2006;84(2):216-24.

Nine subjects, ages 19 to 34 years with a mean age of 24 years, had testing of corneal topography after various tasks in three sessions on separate days early in the morning. The tasks were reading a novel or similar text for 60 minutes, doing microscopy work in which cell counting was done for 60 minutes, and doing Internet browsing and email reading for 60 minutes. Corneal wavefront Zernike coeffi cients up to the fourth order were derived from corneal topography data collected before and after each task. The changes from reading and microscopy were generally larger and more central compared to the changes from computer work. Changes in both lower and higher order aberrations were different between the three tasks. Thus the corneal aberrations induced by these three tasks are different.

VISUAL ACUITYRefraction and visual acuity measurements: what

are their measurement uncertainties? Smith G. Clin Exp Optom 2006;89(2):66-72.

Sources of uncertainty in refraction include depth of focus, uncertainty in test lens powers and vertex distance, and errors in working distance in retinoscopy. Calculation of the overall uncertainty based on estimates of the effects of those sources results in a standard deviation of 0.3 D, which would suggest a 95% confi dence interval of 0.6 D. Sources of uncertainty in visual acuity measurement include pupil size, accommodation, psychological factors, testing protocol, lighting, and chart design. A review of the literature on repeatability of visual acuity measurements suggests an uncertainty of about 0.04 logMAR, which would indicate a 95% confi dence interval of 0.08 logMAR.

AMBLYOPIADecreased cortical activation in response to a

motion stimulus in anisometropic amblyopic eyes using functional magnetic resonance imaging. Bonhomme GR, Liu GT, Miki A, Francis E, et al. J AAPOS. 2006 Dec;10(6):540-6. Epub 2006 Oct 5.

The researchers utilized functional MRI (fMRI) and motion stimuli were used to study whether interocular differences in activation are detectable in motion-sensitive cortical areas in patients with anisometropic amblyopia. They compared the responses in three normal subjects with one with 20/25 acuity and suppression and two anisometropic amblyopes. The control subjects had signifi cant fMRI activation that was comparable on the right and left; the subject with suppression responded the same way. However, the anisometropes exhibited decreased extrastriate activation in their amblyopic eyes compared with the fellow eyes. Their results support the hypothesis that extrastriate cortex is affected in anisometropic amblyopia. Because it was motion sensitivity, it was suggestive of a magnocellular defect, but the exact mechanism is unclear.

Effi ciency of occlusion therapy for management of amblyopia in older children. Brar GS, Bandyopadhyay S, Kaushik S, Raj S. Indian J Ophthalmol. 2006 Dec;54(4):257-60

The goal of this study was to analyze the results of full time occlusion therapy for amblyopia in children older than 6 years. The treatment the children received was full time occlusion of the dominant eye. At initiation of therapy the subjects ranged in age from 6 to 20 years (9.45 +/- 3.11 years). There was a fairly equal mix of strabismic amblyopes and anisometropic amblyopes. Eighty out of 88 eyes (90.0%) had improvement in visual acuity. The response in children older than 12 was reduced. The authors concluded that occlusion therapy yields favorable results in strabismic and/or anisometropic amblyopia, even when initiated for the fi rst time after 6 years of age. After 12 years of age, some children may still respond to occlusion of the dominant eye.

Recurrence of amblyopia after occlusion therapy. Bhola R, Keech RV, Kutschke P, Pfeifer W, et al. Ophthalmol 2006 Nov;113(11):2097-100.

This study was conducted to determine the stability of visual acuity after a standardized occlusion regimen in children with strabismic and/or anisometropic amblyopia. The subjects were four hundred forty-nine patients younger than 10 years who underwent an occlusion trial for amblyopia and were observed until there was a recurrence of amblyopia or for a maximum of 1 year after decrease or cessation of occlusion therapy. A recurrence of amblyopia was defi ned as > or =2 logMAR levels of VA reduction or reversal of fi xation preference within 1 year after a decrease or cessation


of occlusion therapy. Of all the subjects, 27%had a recurrence of amblyopia. The recurrence was found to be inversely correlated with patient age. Interestingly, there was no statistically signifi cant association between the recurrence of amblyopia and VA of the amblyopic eye at the end of maximal occlusion therapy.

Psychosocial impact of amblyopia and its treatment: a multidisciplinary study. Koklanis K, Abel LA, Aroni R. Clin Exp Ophthalmol 2006 Nov;34(8):743-50.

Semistructured in-depth interviews were conducted with children with amblyopia and their parents in an attempt to identify psychosocial factors in the experience and treatment of amblyopia. A psychological inventory was also conducted. Dealing with stigma and the perceptions and responses of peers were found to be of central signifi cance to the experience of amblyopia therapy. There were adverse consequences for some children’s identity and psychosocial well-being. Curiously, the clinical manifestations of amblyopia did not correlate with the social implications of the condition. The authors concluded that while clearly treatment should aim to reverse amblyopia and restore visual acuity, doctors should make efforts to minimize any negative psychosocial consequences of treatment.

Refractive eye surgery in treating functional amblyopia in children. Levenger S, Nemet P, Hirsh A, Kremer I, et al. Binoc Vis Strabismus Q. 2006;21(4):231-34.

This study reported on 11 children with stable refractions and amblyopia who underwent refractive surgery (including one lenticular). Nine of the 11 had myopia and the other two had high astigmatism. The surgical refractive treatment eliminated or reduced the anisometropia, reduced the astigmatic error, improved vision and improved the daily function of the children. They reported no complications or untoward results. The authors’ conclusion was that refractive surgery can be safe and effective in treating children with high myopic anisometropia, high astigmatism, and high myopia. Surgery can improve visual acuity in amblyopia not responding to routine treatment by correcting the refractive error and refractive aberrations.

Thicknesses of the fovea and retinal nerve fi ber layer in amblyopic and normal eyes in children. Kee SY, Lee SY, Lee YC. Korean J Ophthalmol 2006 Sep;20(3):177-81.

This study was designed to compare the thicknesses of the fovea and the retinal nerve fi ber layer in normal children and children with amblyopia. Optical Coherence Tomography (OCT) was performed on 26 children (52 eyes total) with unilateral amblyopia, some due to anisometropia and some strabismus. A normal comparison group of 42 children was also evaluated. No

signifi cant differences in thickness of the fovea or retinal nerve fi ber layer were seen comparing children with amblyopia with those without. However, comparing the children with anisometropic amblyopia and the children with strabismic amblyopia, the average thicknesses of the fovea and the retinal nerve fi ber layer thicknesses were statistically signifi cantly different.

Relationship between anisometropia, patient age, and the development of amblyopia. Donahue SP. J Ophthalmol 2006 Jul;142(1):132-140.

This was a retrospective study of children identifi ed as having anisometropia by photoscreening and then comparing percentage and depth of amblyopia with the children’s age. Only 14% of anisometropic children aged 1 year or younger had amblyopia. Amblyopia was detected in 40% of 2-year-olds, 65% of 3-year-olds, and 76% of 5-year-olds. The depth of the amblyopia also increased with age. Severe amblyopia was rare for children aged 0 to 3, 9% at age 4, and 14% at age 5. The author concluded that younger children with anisometropia have a lower prevalence and depth of amblyopia than older children. By age 3, when most children undergo traditional screening, amblyopia has usually already developed, and this is another compelling argument for earlier identifi cation and intervention particularly in the case of anisometropia.

A randomized trial to evaluate 2 hours of daily patching for strabismic and anisometropic amblyopia in children. Wallace DK; Pediatric Eye Disease Investigator Group, Edwards AR, Cotter SA, Beck RW, Arnold RW, Astle WF, Barnhardt CN, Birch EE, Donahue SP, Everett DF, Felius J, Holmes JM, Kraker RT, Melia M, Repka MX, Sala NA, Silbert DI, Weise KK. Ophthalmol 2006 Jun;113(6):904-12.

The goal of this randomized multicenter clinical trial involving 46 different sites was to compare 2 hours of daily patching (combined with 1 hour of concurrent near visual activities) with a control group of spectacle wear alone for treatment of moderate to severe amblyopia in children 3 to 7 years of age. The subjects had amblyopic-eye visual acuity (VA) of 20/40 to 20/400 associated with strabismus, anisometropia, or both. Randomization of the 180 subjects was either to 2 hours of daily patching with 1 hour of near visual activities or to spectacles alone (if needed). Signifi cant improvements occurred in the patched group and the conclusion was that even after a period of treatment with spectacles, 2 hours of daily patching combined with 1 hour of near visual activities modestly improved moderate to severe amblyopia in children 3 to 7 years old.


Treatment of anisometropic amblyopia in children with refractive correction. Cotter SA; Pediatric Eye Disease Investigator Group, Edwards AR, Wallace DK, Beck RW, Arnold RW, Astle WF, Barnhardt CN, Birch EE, Donahue SP, Everett DF, Felius J, Holmes JM, Kraker RT, Melia M, Repka MX, Sala NA, Silbert DI, Weise KK. Ophthalmol 2006 Jun;113(6):895-903.

This was a prospective, multicenter study aimed at assessing the effectiveness of refractive correction alone for the treatment of previously untreated anisometropic amblyopia in children ages 3 to <7 years old. The authors enrolled eighty-four children 3 to <7 years old with untreated anisometropic amblyopia ranging from 20/40 to 20/250. Optimal refractive correction was provided. Visual acuity improved with optical correction by > or =2 lines in 77% of the patients and resolved in 27%. Improvement took up to 30 weeks for stabilization criteria to be met. The outcome of their treatment was not related to subject age, but was related to better baseline VA and lesser amounts of anisometropia. They concluded that refractive correction alone improved VA in many cases and results in resolution of amblyopia in at least one third of 3- to <7-year-old children with previously untreated anisometropic amblyopia. Most cases of resolution occurred with moderate (20/40-20/100) amblyopia. However, the average 3-line improvement in VA resulting from treatment with spectacles may lessen the burden of subsequent amblyopia therapy for those with worse of amblyopia.

Unilateral visual impairment and neurodevelopmental performance in preschool children. Hrisos S, Clarke MP, Kelly T, Henderson J, Wright CM. Br J Ophthalmol 2006 Jul;90(7):836-38.

The authors looked into consequences of reduced acuity in one eye. In particular they were concerned with the performance of preschool children on tasks requiring visuomotor skills and visuospatial ability. In comparing visually normal children including normal stereoacuity with the amblyopic children, some with normal and some with abnormal stereoacuity, they found some interesting differences. Amblyopia itself did not to relate to visuomotor actions, except when associated with reduced stereoacuity. Stereoacuity had an infl uential role in fi ne visuomotor actions and spatial representation in these preschool children.

Successful treatment of anisometropic amblyopia with spectacles alone. Steele AL, Bradfi eld YS, Kushner BJ, France TD, et al. J AAPOS. 2006 Feb;10(1):37-43.

The authors did a retrospective chart review of the records of 28 patients treated successfully for anisometropic amblyopia with glasses alone. Age, initial visual acuity and stereoacuity, and nature of anisometropia were analyzed to assess associations with time required for resolution, fi nal visual acuity, and stereoacuity. Average time to resolution was about

6 months, and worse best corrected initial visual acuity was associated with longer time to resolution. Age, initial stereoacuity, amount, and type of anisometropia were not associated with time to resolution. They concluded that treatment of anisometropic amblyopia with spectacles alone can be a successful option, and that those patients treated with spectacles alone may experience a lower amblyopia recurrence rate than those treated with occlusion therapy.

COMPUTERS/CVS/VDTSAssociation between occupational asthenopia and

psycho-physiological indicators of visual strain in workers using video display terminals. Ustinaviciene R, Januskevicius V. Med Sci Monit 2006 Jul;12(7):CR296-301. Epub 2006 Jun 28.

This study determined the relationship of functional visual strain and symptoms of asthenopia and to evaluate the association between subjective and objective indicators of visual strain. Visual strain was assessed using a questionnaire. The results noted that 88.5% of the VDT workers complained of various vision disorders. VDT workers who complained of worsened vision, redness of the eyes, eye pain, and diplopia during work were found to show more signifi cant changes in the psycho-physiological indicators objectively refl ecting strain of the vision analyzer. It was concluded that changes in ocular and psycho-physiological function before and at the end of the workday are an appropriate objective measure of visual/central nervous system strain.

Monocular 3D Head Tracking to Detect Falls of Elderly People. Rougier C, Meunier J, St-Arnaud A, Rousseau J. Conf Proc IEEE Eng Med Biol Soc 2006;1:6384-87.

Faced with the growing population of seniors, Western societies need to think about new technologies to ensure the safety of elderly people at home. Computer vision provides a good solution for healthcare systems because it allows a specifi c analysis of people behavior. Moreover, a system based on video surveillance is particularly well adapted to detect falls. They presented a new method to detect falls using a single camera. Their approach was based on the 3D trajectory of the head, which allows them to distinguish falls from normal activities using 3D velocities.

Binocular shape constancy from novel views: the role of a priori constraints. Chan MW, Stevenson AK, Li Y, Pizlo Z. Percept Psychophys 2006 Oct;68(7):1124-39.

Shape constancy was tested from novel views including polyhedra, polygonal lines, and points in 3-D. The results show that constraints such as planarity of surface contours and symmetry are critical for reliable shape constancy. Binocular disparity is used to correct


monocularly reconstructed shape. They noted that, monocular (but not binocular) reconstructions produced correlate well with both monocular and binocular performance. This suggests that binocular and monocular reconstructions of shapes involve similar mechanisms based on monocular shape constraints.

Anxiety, musculoskeletal and visual disorders in video display terminal workers. Tomei G, Rosati MV, Ciarrocca M, Capozzella A, et al. Minerva Med 2006 Dec;97(6):459-66.

This study assessed musculoskeletal and visual disorders and levels of anxiety in 2 groups of VDT operators. This study used 190 VDT operators and 190 controls not assigned to VDT. For VDT operators the relationship between ocular and musculoskeletal symptoms was signifi cant. Their results support current data about musculoskeletal and visual disorders.

The effect of visual training for patients with visual fi eld defects due to brain damage: a systematic review. Bouwmeester L, Heutink J, Lucas C. J Neurol Neurosurg Psychiatr 2007 Jun;78(6):555-64. Epub 2006 Nov 29.

This review evaluated whether systematic visual training leads to (1) a restitution of the visual fi eld (restoration), (2) an increase in the visual search fi eld size or an improvement in scanning strategies (compensation) and (3) a transfer of training-related improvements in activities of daily living such as reading. All studies on scanning compensatory therapy (SCT) found a signifi cant effect, a signifi cant increase in reading speed or decrease in reading errors. It is not clear to what extent patients benefi t from restoration therapy in relation to a more effi cient scanning strategy. No single study has given a satisfactory answer. SCT seems to provide a more successful rehabilitation with simple and user-friendly training techniques. SCT is recommended until the effect of the VRT is defi ned.

Visualization task performance with 2D, 3D, and combination displays. Tory M, Kirkpatrick AE, Atkins MS, Möller T. IEEE Trans Vis Comput Graph 2006 Jan-Feb;12(1):2-13.

This study consisted of a series of experiments that compared 2D displays, 3D displays, and combined 2D/3D for relative position estimation, orientation, and volume of interest tasks. Their results indicated that 3D displays can be very effective for approximate navigation and relative positioning. 3D displays, however are not effective for precise navigation and positioning. They also noted that major factors contributing to display preference and usability were task characteristics, orientation cues, occlusion, and spatial proximity of views that were used together.

Effect of yoga on self-rated visual discomfort in computer users. Telles S, Naveen KV, Dash M, Deginal R, et al. Head Face Med 2006 Dec 3;2:46.

The authors note that dry eye appears to be the main contributor to the symptoms of computer vision syndrome. Various yoga practices have been shown to reduce visual strain in persons with progressive myopia. This randomized controlled trial evaluated the effect of a combination of yoga practices on self-rated symptoms on 291computer uses versus a control group. Both groups were assessed at baseline and after sixty days. The YG group practiced an hour of yoga daily for fi ve days in a week and the control group did their usual recreational activities. The results indicated that after 60 days there was a signifi cantly decreased score in the YG group.

EYE MOVEMENTSOcular motor measures in migraine with and

without aura. Wilkinson F, Karanovic O, Ross EC, Lillakas L, Set al. Cephalalgia 2006;26(6):660-71.

Horizontal pursuits and saccades were measured with an infrared eye movement monitor system in three groups: migraine with aura, migraine without aura, and controls without headaches. They were 19 subjects in each of the three groups. Eye movement parameters studied were pursuit gain (ratio of pursuit velocity to target velocity), pursuit phase (angular measure of how much the pursuits lead ahead or lag behind the target), saccade amplitude, saccade peak velocity, saccade latency (time between onset of stimulus and onset of response), and saccade gain. There were no statistically signifi cant differences between the three groups in any of the saccade or pursuit parameters. The results suggest that visual abnormalities reported in migraine are not the result of abnormal saccades or pursuits.

Age-related changes of vergence under natural viewing conditions. Rambold H, Neumann G, Sander T, Helmchen C. Neurobiol Aging 2006;27(1):163-72.

Vergence eye movements were measured in 32 subjects ranging in age from 19 to 73 years. The subjects were classifi ed into three age groups: twelve subjects 32 years of age or younger, nine subjects 33 to 55 years of age, and eleven subjects 56 years of age or older. Results for the three groups were compared to fi nd whether there were age-related changes in vergence eye movement parameters. Under binocular conditions, there were age-related decreases in peak velocity and acceleration and an increase in latency for a step stimulus (seven degree jump change in stimulus). Accommodative vergence, measured with monocular stimulation, did not show any age-related changes to a step stimulus. Under binocular conditions with a ramp or sinusoidal stimulus (continuous change in stimulus at a rate of 1.5 degrees per second), there were no age-related changes in vergence parameters. Accommodative vergence response to


a continuous stimulus change showed an age-related decrease in velocity and increase in latency. The results suggest that assessments of vergence dynamics should take into account patient age.

A prospective study of the EYEPORT vision training system. Laukkanen H, Rabin J. Optom 2006;77(10):508-14.

Thirty-one university students with an age range of 20 to 41 years (mean age, 25.8 years) participated in a study of the effects of training with the EYEPORT system. A crossover design was used with 14 of the subjects undergoing training for three weeks and the other 17 subjects serving as controls. The during a second three week period, the 17 previously untrained subjects underwent training and the other 14 subjects ceasing their training. Measurements of accommodative facility, vergence facility, reading fi xations, and reading comprehension were taken at baseline, three weeks, and six weeks. Paired t-tests with adjustment of the statistical signifi cance level with the Bonferroni correction for multiple comparisons resulted in signifi cant improvement in vergence facility (p<0.0001) and trends toward improvement in reading fi xations (p<0.015), reading comprehension (p<0.025), and accommodative facility (p<0.035).

Binocular coordination of the eyes during reading. Liversedge SP, Rayner K, White S, Findlay JM, et al. Curr Biol 2006;16(17):1726-29.

Fifteen students at the University of Durham in the United Kingdom had the eye position of both eyes monitored with Purkinje image eye trackers while they read sentences. The sentences were all less than 73 characters and had a target compound noun of six, eight, or ten letters. The target word was presented such that parts of the word could be seen by one eye or the other or the entire word could be seen by both eyes. Fixation with the two eyes during reading averaged 1.1 characters apart (SD=0.8) at the beginning of fi xation and 1.0 characters apart (SD=0.7) at the end of fi xation, one character subtending an angle of 0.29 degrees. When fi xation disparity was present, the lines of sight were more often (93% of fi xations) divergent (uncrossed) than convergent (crossed, 7% of fi xations) in relation to the text. Experiments in which the parts of the target word seen by each eye were varied show that control of saccades is yoked in the two eyes, and is computed based on a fused representation of the word rather than being computed for each eye separately.

Binocular coordination of eye movements during reading. Liversedge SP, White SJ, Findlay JM, Rayner K. Vis Res 2006;46(15):2363-74.

Binocular coordination during was tested in fi fteen students at the University of Durham in the United Kingdom. The position of each eye was monitored with

Purkinje image eye trackers while head movements were minimized with a bite bar and head restraint. Subjects read sentences which were between 48 and 72 characters in length and consisted of 8 to 14 words per sentence. An uncrossed fi xation disparity larger than one character (0.29 degree) was present on 47% of the fi xations and a crossed fi xation disparity was present on 8% of fi xations. Vergence eye movements which served to reduce the fi xation disparity occurred during the fi xations. The magnitude of those vergence eye movements was positively correlated with duration of fi xation.

The binocular coordination of eye movements during reading in children and adults. Blythe HI, Liversedge SP, Joseph HSSL, White SJ, et al. Vis Res 2006;46(22):3898-908.

Twelve adults, ages 18 to 21 years, and twelve children, ages 7 to 11 years, read text with sentences that were 70 to 80 characters long. The position of each eye was monitored with Purkinje image eye trackers while head movements were minimized with a bite bar and forehead rest. Fixation disparity often was present during fi xations with vergence eye movements during fi xation changing the fi xation disparity. For adults, at the end of fi xation, there was alignment 48% of the time, crossed disparity 13% of the time, and uncrossed disparity 39% of the time. For children, there was 39% of the time at the end of fi xation, crossed disparity 24% of the time, and uncrossed disparity 37% of the time. The mean amount of disparity at the end of fi xation was 1.26 characters for adults and 1.58 characters for children, with one character being 0.29 degree. The disparity magnitude was signifi cantly greater in children than in adults (p<0.001).

Eye movements when reading disappearing text: the importance of the word to the right of fi xation. Rayner K, Liversedge SP, White SJ. Vis Res 2006;46(3):310-23.

Fifty-six young adult native English speakers participated as subjects in a series of experiments in which sentences were read and either the currently fi xated word or the word to the right of it or both disappeared or was masked during fi xation. Masking was done by replacing a word with Xs. Words reappeared when a saccade was made to another word, either to the right or to the left. Reading was disrupted much more when the word to the right of fi xation disappeared or was masked than when the word fi xation disappeared or was masked. The duration of fi xation was less on words which were more frequent in the reading material.


Smooth pursuit eye movements in children. Salman MS, Sharpe JA, Lillikas L, Dennis M, et al. Exp Brain Res 2006;169(1):139-43.

Smooth pursuit eye movements were recorded by infrared eye tracker in 38 children in the 8 to 19 year age range. The visual targets were moved sinusoidally at a 10 degree amplitude and a frequency of 0.25 or 0.5 Hz (cycles per second), horizontally and vertically. Mean pursuit gains (ratio of eye velocity to target velocity) for horizontal movements were 0.84 at 0.25 Hz and 0.73 at 0.50 Hz. Mean gains for vertical pursuits were 0.68 at 0.25 Hz and 0.45 at 0.5 Hz. Pursuit gains were signifi cantly higher for horizontal pursuits than for vertical pursuits, were signifi cantly higher for 0.25 Hz than for 0.5 Hz, and increased signifi cantly with age. Horizontal pursuit gains reached reported adult levels by mid adolescence.

Improvements in performance following optometric vision therapy in a child with dyspraxia. Hurst CMF, Van de Weyer S, Smith C, Adler PM. Ophthal PhysiolOpt 2006;26(2):199-210.

An eight year old boy diagnosed with dyspraxia was given a three month course of occupational therapy and an eight month program of vision therapy. The diagnosis of dyspraxia was made by a pediatric occupational therapist based on observed poor proprioception, delayed bilateral integration, and poor visual perception. Vision therapy resulted in improvements in fusional vergence ranges, accommodative facility, saccades, and pursuits. Reading level improved by four years in eleven months. Occupational therapy Sensory Integration and Praxis Test visual and motor/visual perception subtests also showed improvement.

Infantile nystagmus: current concepts in diagnosis and management. Abel LA. Clin Exp Optom2006;89(2):57-65.

This is a review paper which summarizes present concepts on the diagnosis and management of congenital nystagmus. Congenital nystagmus may exist in either jerk or pendular form. Another form known as dual jerk nystagmus is a composite waveform of both jerk and pendular oscillations. Some textbooks state that absence of oscillopsia is an indication of congenital nystagmus, but some patients with congenital nystagmus have been reported to have oscillopsia at least occasionally. Electroretinography and visual evoked potential testing can be useful in evaluating the visual sensory pathways in childhood nystagmus. In latent nystagmus the direction of the fast phase is away from the covered eye. That change in direction of fast phase with change in which eye is seeing is unique to congenital nystagmus. Common treatment approaches include surgery, prism spectacles, contact lenses, and vision therapy. Vision therapy may be helpful in that strabismic patients can have a “latent-manifest latent nystagmus” when they

are suppressing, which can be eliminated when the strabismus is eliminated.

VISION SCREENINGField evaluation of the Welch Allyn SureSight

vision screener: incorporating the vision in preschoolers study recommendations. Rowatt AJ, Donahue SP, Crosby C, Hudson AC, et al. J AAPOS. 2007. Jun;11(3):243-8. Epub 2006 Nov 30.

This was a prospective Vision in Preschoolers (VIP) study that evaluated 11 methods of screening and proposed referral criteria for the Welch Allyn SureSight(trade mark) Vision Screener. The SureSight had a higher sensitivity than most other screening techniques. The conclusions noted that the SureSight can be used successfully for preschool screening.

Right to sight: accessing eye care for adults who are learning disabled. Starling S, Willis A, Dracup M, Burton M, et al.. J Intellect Disabil Res.. 2006 Dec;10(4):337-55.

Of the 146 learning disabled adults assessed, it was found that 39 percent received less eye care than the general population. Those living with families or independently were signifi cantly less likely to have had an eye examination than people living with paid support staff. It was also noted that 30 percent of those previously examined had been diagnosed with eye problems and 43 percent of those previously prescribed glasses were reported as unable to tolerate them.

A comparison of patched HOTV visual acuity and photoscreening. Leman R, Clausen MM, Bates J, Stark L, et al.. J Sch Nurs 2006 Aug;22(4):237-43.

This study compared portable acuity testing with photoscreening of 1,700 preschoolers, kindergarteners, and 1st-graders. School nurses performed patched acuity testing and two types of photoscreening. The results indicated that using a Gateway DV-S20 digital camera was signifi cantly more sensitive to children with signifi cant vision problems.

Relationship between anisometropia, patient age, and the development of amblyopia. Donahue SP. Am J Ophthalmo. 2006 Jul;142(1):132-40.

This was a retrospective observational study of preschool children with anisometropia. The results noted that 14% of anisometropic children aged 1 year or younger had amblyopia. Amblyopia was detected in 40% of 2-year-olds, 65% of 3-year-olds, and 76% of 5-year-olds. Amblyopia depth increased with age. Children with strabismus had a stable prevalence and depth of amblyopia. It was concluded that younger children with anisometropia have a lower prevalence and depth of amblyopia than older children. By age 3, when most


children undergo traditional screening, amblyopia has already developed.

Preschool vision screening in pediatric practices. Kemper AR, Clark SJ. Clin Pediatr (Phila) 2006 Apr;45(3):263-66.

This study used a national sample of pediatricians (55% response rate) to evaluate preschool vision screening practices. Acuity screening for 3-year-old children was 35%, but increased for 4- (73%) and 5-year-old children (66%). Few used photoscreening or autorefraction (8%). Noted barriers to screening were that it was too time-consuming and children are uncooperative. Half reported that there should be separate reimbursement for vision screening.

The Pediatric Vision Screener III: detection of strabismus in children. Nassif DS, Piskun NV, Hunter DG. Arch Ophthalmol 2006 Apr;124(4):509-13.

Seventy-seven subjects 2 - 18 years of age received orthoptic examinations and were classifi ed as at risk for amblyopia if strabismus or anisometropia (>1.50 diopters) was present. Subjects were then tested with the PVS. The results indicated that binocularity as determined by the PVS was greater than 65% for all controls and less than 20% for all subjects with constant strabismus. All subjects with anisometropia and no strabismus had binocularity scores less than 10%.

PEDIATRIC PATHOLOGYSystemic and ocular fi ndings in 100 patients with

optic nerve hypoplasiaGarcia ML, Ty EB, Taban M, David Rothner A, et

al.. J Child Neurol 2006 Nov;21(11):949-56.In this study a retrospective record review of 100

patients with optic nerve hypoplasia for the presence of neurologic, radiologic, and endocrine abnormalities was performed. It was noted that conditions previously associated with optic nerve hypoplasia and present in our patients included premature birth in 21%, fetal alcohol syndrome in 9%, maternal diabetes in 6%, and endocrine abnormalities in 6%. Developmental delay was present in 32%, cerebral palsy in 13%, and seizures in 12%. There was an associated neurologic abnormality in 57% of patients with bilateral optic nerve hypoplasia and 32% with unilateral optic nerve hypoplasia.

Pediatric eye injury-related hospitalizations in the United States. Brophy M, Sinclair SA, Hostetler SG, Xiang H. Pediatrics 2006 Jun;117(6):e1263-71.

2.4 million eye injuries occur in the United States each year (35% aged 17 years or less). 3834 eye injury-related hospitalizations were analyzed. Inpatient charges for the treatment of these injuries were more than $88 million. Hospitalization for pediatric eye injuries in the US in 2000 was 8.9 per 100,000 persons aged 20 years

or less. The conclusions noted that their is considerable morbidity, fi nancial burden, and proximal causes for pediatric eye injury-related hospitalizations.

Anesthetic management of preschool children with penetrating eye injuries: postal survey of pediatric anesthetists and review of the available evidence. Seidel J, Dorman T. Paediatr Anaesth 2006 Jul;16(7):769-76.

Pediatric anesthetists were surveyed regarding their anesthesia management of a screaming child with a penetrating eye injury. Of those responding 21.2% had never seen a single case, 55.1% had seen <5, 17.8% had seen 5-10, and 5.9% had seen >10 cases. More experienced anesthetists preferred the use of techniques without relaxants and to extubate children under deep anesthesia. The conclusions noted that few have extensive experience managing a penetrating eye injury in a child

A symptom survey and quality of life questionnaire for nasolacrimal duct obstruction in children. Holmes JM, Leske DA, Cole SR, Chandler DL, Repka MX; Nasolacrimal Duct Obstruction Questionnaire Study Group, Silbert DI, Tien DR, Bradley EA, Sala NA, Levin EM, Hoover DL, Klimek DL, Mohney BG, Laby DM, Lee KA, Enzenauer RW, Bacal DA, Mills MD, Beck RW; Pediatric Eye Disease Investigator Group. Ophthalmol 2006 Sep;113(9):1675-80. Epub 2006 Jul 7.

The purpose of this study was to develop and validate a new parental questionnaire addressing symptoms and health-related quality of life (HRQL) in childhood nasolacrimal duct obstruction (NLDO). The conclusions noted that the NLDO questionnaire is useful in quantifying parental perception of symptoms and HRQL in childhood NLDO and that the questionnaire may have a role in future clinical study of NLDO.

Identifi cation of pain indicators for infants at risk for neurological impairment: a Delphi consensus study. Stevens B, McGrath P, Yamada J, Gibbins S, et al.. BMC Pediatr. 2006 Feb 2;6:1.

The purpose of this study was to establish consensus about which behavioral, physiologic and contextual indicators best characterize pain in infants at high, moderate and low levels of risk for neuro-impairment. Results noted that pain indicators with the highest concordance for all groups were brow bulge, facial grimace, eye squeeze, and inconsolability. Increased heart rate from baseline in the moderate and severe groups demonstrated high concordance as well.


EXCEPTIONAL PATIENTSEffect of CX516, an AMPA-modulating compound,

on cognition and behavior in fragile X syndrome: a controlled trial. Berry-Kravis E, Krause SE, Block SS, Guter S, et al. J Child Adolesc Psychopharmacol. 2006 Oct;16(5):525-40.

A Phase II, 4-week randomized, double-blind, placebo-controlled clinical trial was conducted to evaluate the safety and effi cacy of the Ampakine compound CX516 as a potential treatment for the underlying disorder in fragile X syndrome (FXS). Cognitive and behavioral outcome measures were administered prior to and at the end of treatment, and again at 2 weeks post treatment. The results indicated that there were no signifi cant improvements in memory, the primary outcome measure, or in secondary measures of language, attention/executive function, behavior, and overall functioning. This study did demonstrate that many outcome measures were reproducible in this test-retest setting for the FXS population.

Visual function and execution of microsaccades related to reading skills, in cerebral palsied children. Kozeis N, Anogeianaki A, Mitova DT, Anogianakis G, Mitov T, et al. Int J Neurosci. 2006 Nov;116(11):1347-58.

This article assesses the ability of cerebral palsy children to execute microsaccades. The results showed that the microsaccadic skills were severely affected with only 19% of the CP children having normal function. 20.9% demonstrated with an oculomotor problem, 32.4% had a visual-perceptual problem, and 27.7% had a combined oculomotor and visual perceptual problem. CP children, in the absence of severe mental retardation, have very poor visual skills and visual perception that leads to reading diffi culties.

Gross and fi ne motor function and accompanying impairments in cerebral palsy. Himmelmann K, Beckung E, Hagberg G, Uvebrant P. Dev Med Child Neurol 2006 Jun;48(6):417-23

This study described gross and fi ne motor function and accompanying neurological impairments in children with cerebral palsy. This study found that motor function differed between CP types. More severe levels correlated with larger proportions of accompanying impairments and in children born at term, to the presence of adverse peri/neonatal events. They conclude that the classifi cation of CP should be based on CP type and motor function, since the two combine to produce a better indicator of total impairment.

Vision in children with hydrocephalus. Andersson S, Persson EK, Aring E, Lindquist B, Dutton GN, et al. Dev Med Child Neurol 2006 Oct;48(10):836-41.

This study noted that vision function defi cits were identifi ed in 83% of the children with hydrocephalus.

Visual impairment was found in 15%. 69% had strabismus and 67% refractive error. Cognitive visual dysfunction was seen in 59%. They also stated that visual disorders were most frequent in those with epilepsy, cerebral palsy, and/or cognitive disability.

Long-term graft survival in patients with Down syndrome after penetrating keratoplasty. Wroblewski KJ, Mader TH, Torres MF, Parmley VC, et al. Cornea 2006 Oct;25(9):1026-28.

This retrospective study determined the graft survival and long-term visual outcome after penetrating keratoplasty (PK) for patients with Down Syndrome and keratoconus. The results indicated that 21 PKs were performed on 18 eyes of 13 patients. Three PKs were repeated for secondary graft failure. All 18 eyes had clear grafts at the patient’s last evaluation. Follow-up ranged from 4 to 88 months, with a mean of 34.9 months. Preoperative visual acuity was from 20/160 to count fi ngers. Postoperatively, visual acuity was from 20/30 to 20/200. It was concluded that clear grafts and improvements in visual acuity can be obtained for patients with Down syndrome. Careful postoperative follow up by care givers is very important.

Laterality in persons with intellectual disability II. Hand, foot, ear, and eye laterality in persons with Trisomy 21 and Williams-Beuren syndrome. Gérard-Desplanches A, Deruelle C, Stefanini S, Ayoun C, Vet al. Dev Psychobiol 2006 Sep;48(6):482-91.

This study assessed laterality in individuals with Trisomy 21 and Williams-Beuren syndrome (WBS). Handedness was also assessed. Those with Down Syndrome were more frequently left- or mixed-handed. Individuals with WBS had intermediate scores. Differences in IQ did not correlate with laterality scores. The conclusion was that laterality profi les were not the same in the two groups.

Strabismus in Down syndrome. Yurdakul NS, Ugurlu S, Maden A. J Pediatr Ophthalmol Strabismus 2006 Jan-Feb;43(1):27-30.

Fifty-seven patients with Down Syndrome were given comprehensive examinations that included an assessment of ocular alignment, cycloplegic refraction and dilated fundus examination. The results noted that 19% had strabismus (18%esotropia and 2% exotropia). Infantile esotropia was seen in 3 patients whith no signifi cant refractive error. Seven of the patients had acquired esotropia with clinically signifi cant refractive error and anisometropia. A higher incidence of hypermetropia was noted in patients with strabismus. The conclusions stated that both esotropia and hypermetropia were commonly seen.


Sensory impairments and health concerns related to the degree of intellectual disability in people with Down syndrome . Määttä T, Kaski M, Taanila A, Keinänen-Kiukaanniemi S, et al. Downs Syndr Res Pract 2006 Sep;11(2):78-83.

Individuals with Down syndrome have a number of health problems, including congenital heart defect, visual impairment, hearing loss, autoimmune diseases, epilepsy, early-onset Alzheimer’s disease and intellectual disability. This paper assessed the affect of impaired health on cognitive performance in those with Down syndrome. 129 individuals with Down syndrome were studied. The results indicated that health issues were related to the individuals’ cognitive levels. Visual impairment, dental health and neurological anomalies were associated with the level of intellectual disability and age.

Global and local processing in Williams syndrome, autism, and Down syndrome: perception, attention, and construction . Porter MA, Coltheart M. Dev Neuropsychol 2006;30(3):771-89.

Williams Syndrome (WS), autism (AS), and Down Syndrome (DS) individuals were assessed for global and local processing using perception, attention, and construction tasks. Their results suggest a bias in attention toward local processing as well as a global bias in attention in DS. This study fi nds support for a hierarchical defi cit theory in a subset of WS individuals but not in DS or AS.

Perceptual-motor defi cits in children with Down syndrome: implications for intervention.. Virji-Babul N, Kerns K, Zhou E, Kapur A, et al. Downs Syndr Res Pract 2006 Jul;10(2):74-82.

Since recent evidence suggests that motor milestones have limited predictive power for long-term motor outcomes, researchers have begun to study the underlying perceptual-motor competencies that affect motor behavior in those with Down syndrome. The results indicate that children with Down syndrome are able to make basic perceptual discriminations but show impairments in the perception of complex visual motion cues.

Ocular motor indicators of executive dysfunction in Fragile X and Turner syndromes. Lasker AG, Mazzocco MM, Zee DS. Brain Cog 2007 Apr;63(3):203-20. Epub 2006 Nov 14.

Fragile X and Turner syndromes are two X-chromosome-related disorders associated with executive function and visual spatial defi cits. This study used ocular motor paradigms to examine evidence that disruption to different neurological pathways underlies these defi cits. It was noted that females with fragile X had defi cits in memory-guided saccades, predictive saccades, and saccades made in the overlap condition of a gap/overlap

task. Females with Turner syndrome showed problems in generating memory-guided saccades, but not during either the predictive saccade or gap/overlap task. Females with Turner syndrome, but not females with fragile X, showed defi cits in visually guided saccades and anti-saccades. These fi ndings suggest that different brain regions are affected in the two disorders, and that different pathways lead to similar cognitive phenotypes noted for Fragile X and Turner syndromes.

Enhanced perfusion in eyes and cerebral perfusion defects in a patient with Fragile X Syndrome . Balci TA, Ciftci I, Kabakus N, Aydin M. Tohoku J Exp Med 2006 Oct;210(2):169-73.

In this study, brain perfusion single photon emission computed tomography (SPECT) was performed on a 6 y/o Fragile X male (FXS). An enhanced uptake of HMPAO in the orbits may refl ect the pathology associated with FXS, because patients with FXS might have visual-motor abnormalities.

Eye movement and visual search: are there elementary abnormalities in autism? Brenner LA, Turner KC, Müller RA. J Autism Dev Disord 2007 Aug;37(7):1289-309. Epub 2006 Nov 21.

An atypical eye gaze is frequently observed in those with autism, but little is known about the underlying oculomotor abnormalities. Our review of visual search and oculomotor systems in the healthy brain suggests that relevant networks may be partially impaired in autism. Eye movement abnormalities may play a role in functions known to be impaired in autism, ie: imitation and attention. Oculomotor abnormalities may play a role as a sensorimotor defect at the root of impairments in later developing functional systems resulting in potential sociocommunicative defi cits.

Saccadic movements using eye-tracking technology in individuals with autism spectrum disorders: pilot study. Mercadante MT, Macedo EC, Baptista PM, Paula CS, et al.. Arq Neuropsiquiatr 2006 Sep;64(3A):559-62.

This study assesses differences in the visual scanning between pervasive developmental disorders (PDD) and controls. The results indicated that those with PDDG had longer duration of saccadic movements for social pictures compared to the control group. These fi ndings suggest differences in strategies between the PDD and CG groups.

A role for the ‘magnocellular advantage’ in visual impairments in neurodevelopmental and psychiatric disorders. Laycock R, Crewther SG, Crewther DP. Neurosci Biobehav Rev 2007;31(3):363-76. Epub 2006 Dec 1.

Abnormal visual information processing and visual attention anomalies are noted in a number of


neurodevelopmental and psychiatric disorders. An integrated model of visual processing based on single cell and human electrophysiology may allow us to better understand how the visual system and the magnocellular pathways are involved.

Visual form-processing defi cits in autism. Spencer JV, O’Brien JM Perception. 2006;35(8):1047-55.

Those with autism have a number of defi cits in object recognition and global processing. This study compared detection thresholds for children with autism, children with Asperger syndrome, and a matched control group. Those with autism showed a signifi cant form-coherence defi cit and a signifi cant motion-coherence defi cit, while the performance of the children with Asperger syndrome did not differ signifi cantly from that of controls.

Autism and attention defi cit hyperactivity disorder: assessing attention and response control with the integrated visual and auditory continuous performance test. Corbett BA, Constantine LJ. Child Neuropsychol. 2006 Aug;12(4-5):335-48.

Attention defi cit hyperactivity disorder (ADHD) have been widely reported in children with autism (ASD). This study investigated attention and response control in children with ASD, ADHD, and typical development using an Integrated Visual and Auditory Continuous Performance Test. Many children with ASD show defi cits in visual/auditory attention and greater defi cits in impulsivity than children with ADHD or typical development.

NEURO-OPTOMETRY/NEUROLOGICAL INSULT

Occurrence of ocular disease in traumatic brain injury in a selected sample: a retrospective analysis. Rutner D, Kapoor N, Ciuffreda KJ, Craig S, et al. Brain Inj 2006 Sep;20(10):1079-86.

This retrospective study determined the risk of ocular disease in a selected, visually-symptomatic sample of clinic patients having traumatic brain injury vs. cerebrovascular accident. The conclusions noted that individuals with TBI exhibited corneal abrasions, blepharitis, chalazion/hordeolum, dry eye, traumatic cataract, vitreal prolapse and optic atrophy. This is different from those eye problems unique to CVA, which included sub-conjunctival hemorrhage and ptosis.

The incidence of visual perceptual impairment in patients with severe traumatic brain injury. McKenna K, Cooke DM, Fleming J, Jefferson A, et al. Brain Inj 2006 May;20(5):507-18.

This study investigated the visual perceptual impairments in patients with traumatic brain injury. The conclusions noted that visual perceptual anomalies are evident in patients with severe TBI when compared to a normative sample. Routine use of screening tools can

help identify visual perceptual impairments in these patients.

The role of prefrontal cortex in visuo-spatial planning: A repetitive TMS study. Basso D, Lotze M, Vitale L, Ferreri F, et al. Exp Brain Res 2006 May;171(3):411-5. Epub 2006 Apr 27.

In this study subjects had to decide which order of locations optimizes total task travel time and distance. The results indicate that, in a visuo-spatial problem-solving task, the prefrontal cortex is involved in the switching between heuristics during the execution of a plan.

Human spatial navigation defi cits after traumatic brain injury shown in the arena maze, a virtual Morris water maze. Skelton RW, Ross SP, Nerad L, Livingstone SA. Brain Inj 2006 Feb;20(2):189-203.

This study examined such visual spatial defi cits and conducted a detailed analysis of navigational behavior in a virtual environment. The conclusions noted that virtual environments can be used to assess the presence of spatial navigation defi cits after TBI.

Tracking the recovery of visuospatial attention defi cits in mild traumatic brain injury. Halterman CI, Langan J, Drew A, Rodriguez E, et al. Brain. 2006 Mar;129(Pt 3):747-53. Epub 2005 Dec 5.

This study probed defi cits in the alerting, orienting and executive components of visuospatial attention in individuals who have mild traumatic brain injury. The fi ndings showed that the orienting and executive components were signifi cantly affected by TBI immediately after the injury, whereas the alerting component was not. Participants with mild TBI recovered from the defi cits in the orienting component of attention within a week of their injury; however the defi cits in the executive component remained throughout the month post-injury. This study indicates that the regions of the brain associated with the orienting and executive components of visuospatial attention are most susceptible to neural damage resulting from mild TBI.

Virtual reality applications for the remapping of space in neglect patients. Ansuini C, Pierno AC, Lusher D, Castiello U. Restor Neurol Neurosci 2006;24(4-6):431-41.

This article presents evidence of the potential of virtual reality (VR) for the assessment, training and recovery of hemispatial neglect. The conclusions note that it is possible to re-create links between the affected and the nonaffected space in neglect patients by using VR. Furthermore, that specifi c regions may play a crucial role in the recovery of space that underlies the improvement of neglect patients when trained with virtual reality.


Monocular patching in subjects with right-hemisphere stroke affects perceptual-attentional bias. Barrett AM, Burkholder S. J Rehabil Res Dev 2006 May-Jun;43(3):337-46.

In this study, 6 post-stroke subjects bisected lines while self-monitoring their performance via a camera/video apparatus. The subjects were tested with and without right and left eye patches. It was noted that patching did not affect group line-bisection error, but both right and left patches decreased individual subject spatial bias. When each subject was individually, patching improved performance in subjects who had greater spatial biases. They concluded that monocular patching may primarily affect post-stroke spatial bias.

Sensory and cognitive association in older persons: fi ndings from an older Australian population. Tay T, Wang JJ, Kifl ey A, Lindley R, et al. Gerontol 2006;52(6):386-94. Epub 2006 Aug 18.

This study assessed the correlation between sensory and cognitive function across groups with a narrow age range and any independent association between sensory and cognitive impairment. They found cognitive impairment in 3.3% of the subjects, vision impairment in 2.7% and moderate to severe hearing loss in 10.5% of this population. The conclusions noted that they had documented an age-related correlation between sensory and cognitive function in a normal ageing sample and that their data suggested that age-related decline and the effect of visual impairment on the measurement of cognition only partly explain the association between sensory and cognitive impairments in seniors.

How to identify potential fallers in a stroke unit: validity indexes of 4 test methods. Andersson AG, Kamwendo K, Seiger A, Appelros P. J Rehabil Med 2006 May;38(3):186-91.

This study described general characteristics of patients with stroke who have a tendency to fall and to determine whether certain test instruments can identify fallers. The conclusions noted that the Berg Balance Scale, Stops Walking When Talking and the TUG can be used to evaluate which patients have a tendency to fall.

Impact of alertness training on spatial neglect: a

behavioural and fMRI study. Thimm M, Fink GR, Küst J, Karbe H, et al. Neuropsychologia 2006;44(7):1230-46. Epub 2005 Nov 8.

This paper studied the effects of a 3-week computerized alertness training on chronic visuospatial hemineglect. The results show that a 3-week program of computerized alertness training improves performance both in alertness and neglect tests. The limited stability of these effects over time suggests that a 3-week alertness training alone does not result in long lasting, but refi ning the treatment protocol may lead to a more stable amelioration of neglect symptoms.

PERCEPTUAL PROCESSESHandwriting diffi culties in primary school

children: a search for underlying mechanisms. Volman MJ, van Schendel BM, Jongmans MJ. Am J Occup Ther 2006 Jul-Aug;60(4):451-60.

The authors looked at perceptual-motor dysfunction and cognitive planning problems and their association with the quality or speed of handwriting in children with handwriting problems. When subjects with handwriting problems and a control group were tested with regard to visual perception, visual-motor integration, fi ne motor coordination, and cognitive planning abilities, the group with handwriting problems scored signifi cantly lower on visual perception, visual-motor integration, fi ne motor coordination, and cognitive planning in comparison with classroom controls. The only signifi cant predictor for quality of handwriting in the poor handwriting group was visual-motor integration, whereas fi ne motor coordination was the only signifi cant predictor of quality of handwriting in the control group. The authors concluded that two different mechanisms underlie the quality of handwriting in children with and without handwriting problems, and that poor quality of handwriting of children with handwriting issues seems particularly related to a defi ciency in visual-motor integration.

Visuo-motor integration and control in the human posterior parietal cortex: evidence from TMS and fMRI. Iacoboni M. Neuropsychologia 2006;44(13):2691-99.

The posterior parietal cortex is a fundamental structure for visuo-motor integration and control. The author interprets recent transcranial magnetic stimulation (TMS) and functional magnetic resonance imaging (fMRI) studies. The author suggests that these studies reveal four concepts about visual-motor integration and the posterior parietal cortex. These are: that the human posterior parietal cortex has enlargened through evolution, that visual-motor control in the posterior parietal cortex may be implemented by coding primarily action goals, that the lateralization of visuo-motor functions in the posterior parietal cortex suggests that the left posterior parietal cortex is more concerned with tool use and the right posterior parietal cortex is more concerned with imitation of the actions of others, and that visuo-motor inter-hemispheric transfer through parietal callosal fi bers occurs at the level of ‘motor intention’.

Working memory in children with reading disabilities. Gathercole SE, Alloway TP, Willis C, Adams AM. J Exp Child Psychol 2006 Mar;93(3):265-81.

This study investigated associations between working memory and both reading and mathematics abilities in a sample of 46 6- to 11-year-olds with reading disabilities.


Their fi ndings suggest that working memory skills represent an important constraint on the acquisition of skill and knowledge in reading and mathematics. They discuss possible mechanisms for the contribution of working memory to learning, and the implications for educational practice.

Retinotopic effects during spatial audio-visual integration. Meienbrock A, Naumer MJ, Doehrmann O, Singer W, Muckli L. Neuropsychologia 2007 Feb 1;45(3):531-39.

In order to integrate visual and auditory stimuli we need information about whether visual and auditory signals originate from corresponding places in the external world. The authors studied spatially congruent and incongruent audio-visual (AV) stimulation. They used functional magnetic resonance imaging (fMRI) and found two distinct networks of cortical regions that processed preferentially either spatially congruent or spatially incongruent AV stimuli. Early visual areas responded preferentially to incongruent AV stimulation and higher visual areas of the temporal and parietal cortex responded preferentially to congruent AV stimulation. They concluded that during mismatch processing, whenever a spatial mismatch is detected in multisensory regions then processing resources are re-directed to low-level visual areas.

READING/DYSLEXIAVisual-evoked response, pattern

electroretinogram, and psychophysical magnocellular thresholds in glaucoma, optic atrophy, and dyslexia. Vaegan, Hollows FC. Optom Vis Sci 2006 Jul;83(7):486-98.

The examiners took tests and targets designed to be optimal for the magnocellular system and evaluated four groups: suspects and patients with early glaucoma, patients with optic nerve disease, dyslexic children, and age-matched controls. Parvocellular-specifi c responses were normal, except in cases with explicable visual acuity loss. They found a clear dichotomy and low correlations between psychophysics and electrophysiology both within and between groups. Psychophysical threshold elevations were absent in all glaucoma groups, often large in optic atrophy and small (2.5%) but highly signifi cant in dyslexia. They concluded that contrast thresholds to magnocellular-specifi c stimuli were consistent in cortex and retina but VEPs were more reliable. They found no VEP loss in dyslexia which suggested that other losses seen were artifacts. They did conclude that further research is needed and that maybe the frequency-doubling technology might be more useful clinically.

Isolating the impact of visual perception on dyslexics’ reading ability. Shovman MM, Ahissar M. Vis Res 2006 Oct;46(20):3514-25.

The authors initially comment that lots of data suggest phonology plays a role in dyslexia, but that the role of vision is still highly debated. They devised a task similar to single word reading. Young adult dyslexics, with average or above general cognitive abilities, and controls matched for age and cognitive skills participated in the study. They measured contrast thresholds for identifying unfamiliar letters, which were chosen from an alphabet graphically similar to Hebrew and English but unfamiliar to the subjects. They looked at the effects of decreasing letter size, increasing letter crowding and adding white noise. They found that dyslexics performed as well as controls under all test conditions, and consequently concluded that, despite the data showing that dyslexics have marked diffi culties with single word reading, the cause of these diffi culties is not a visual processing defi cit.

Directional motion contrast sensitivity in developmental dyslexia. Slaghuis WL, Ryan JF. Vis Res 2006 Oct;46(20):3291-303.

In this study the researchers compared motion perception for drifting gratings in two dyslexia classifi cation schemes: the dyseidetic, dysphonetic and mixed subgroups and surface, phonological and mixed subgroups. Subjects were a sample of 32 children with dyslexia and 32 matched normal readers. Their fi ndings showed that there were no differences in motion direction perception between normal readers and the group with dyslexia when dyslexia was taken as a homogeneous group. The direction perception was found to be normal in the dyseidetic and surface dyslexia subgroups but signifi cantly lowered in both mixed dyslexia subgroups. One unpredicted inconsistency in the fi ndings was that motion direction perception was signifi cantly lowered in the dysphonetic subgroup but normal in the phonological subgroup. In addition, they showed evidence for the presence of a disorder in sequential and temporal order processing that appeared to refl ect a problem in retaining sequences of non-meaningful auditory and visual stimuli in short-term working memory in children with dyslexia.

Do children with developmental dyslexia show a selective visual attention defi cit? Sireteanu R, Goebel C, Goertz R, et al. Strabismus. 2006 Jun;14(2):85-93.

The authors investigated the performance of children with developmental dyslexia on a number of visual tasks requiring selective visual attention. Dyslexic children did not show the overestimation of the left visual fi eld (pseudo-neglect) characteristic of normal adult vision. The performance of dyslexic children in texture segmentation and feature search tasks was identical to that of control children matched for age, gender and


intelligence. However, when tested on conjunction tasks for orientation and form, dyslexic children showed shorter reaction times and a dramatically increased number of errors. Differences between the two groups decreased with increasing age. These results suggest that children with developmental dyslexia present selective defi cits in visual attention.

Do phonologic and rapid automatized naming defi cits differentially affect dyslexic children with and without a history of language delay? A study of Italian dyslexic children. Brizzolara D, Chilosi A, Cipriani P, Di Filippo G, et al. Cogn Behav Neurol 2006 Sep;19(3):141-9.

The authors wanted to see if phonologic and rapid automatized naming (RAN) defi cits were present and associated in Italian dyslexic children and also whether they differentially affect dyslexics with and without a history of previous language delay. Thirty-seven children were selected on the basis of a reading defi cit and were assigned to 2 groups according to whether or not they had a history of early language delay. They observed that RAN defi cits were shared by most dyslexics whether they had a history of language delay or not. Phonologic defi cits were mainly associated with a previous language delay. They concluded that in a shallow orthography such as Italian, RAN, not phonologic defi cits, may represent the main cognitive marker of developmental dyslexia.

Screening for Meares-Irlen sensitivity in adults: can assessment methods predict changes in reading speed? Hollis J, Allen PM. Ophthal Physiol Opt 2006 Nov;26(6):566-71.

The authors wanted to see which of two methods of assessing candidates for colored overlays had the most practical utility. A total of 58 adults were assessed as potential candidates for colored overlays, using two methods; a questionnaire, which identifi ed self-reported previous symptoms, and a measure of perceptual distortions immediately prior to testing. Participants were classifi ed as normal, Meares-Irlen sensitive, and borderline sensitive. Reading speed was measured with and without colored overlays. Normal subjects did not show any signifi cant benefi t from reading with an overlay. A signifi cant reading advantage was found for the borderline and Meares-Irlen participants using an overlay. The authors suggest that the assessment of perceptual distortions immediately prior to measuring color preference and reading speed is the most meaningful method of assessing pattern glare and determining the utility of colored overlays.

Attentional shifting and the role of the dorsal pathway in visual word recognition. Pammer K, Hansen P, Holliday I, Cornelissen P. Neuropsychologia 2006;44(14):2926-36.

The authors review the dorsal visual pathway and its role in the control of guided visual search mechanisms. The point out that it has been suggested recently that the dorsal visual pathway is specifi cally involved in the spatial selection and sequencing required for orthographic processing in visual word recognition. They manipulated the demands for spatial processing in a word recognition, lexical decision task. Neuroimaging revealed high frequency right posterior parietal activation consistent with dorsal stream involvement. This result provides neurophysiological evidence that the dorsal visual stream may play an important role in visual word recognition and reading. The authors further conclude that a plausible link between early stage theories of reading, and the magnocellular-defi cit theory of dyslexia, which characterizes many types of reading diffi culty, was seen.

It’s coming...

...Save the Date

COVD 38th Annual Meeting October 13-18, 2008

Rancho Las Palmas Palm Springs, California

2006 annual review of the literature...emmetropic. myopia was deﬁ ned as minus refraction of at...

Documents