Prevalence of corneal astigmatism in cataract surgery candidates

in Bangkok, Thailand

Kaevalin Lekhanont, MD, Wadakarn Wuthisiri, MD, Porntip Chatchaipun, BSc, Anun Vongthongsri, MD

Ramathibodi Hospital, Mahidol University

The authors have no proprietary interest in any product or instrument used in this study

Purpose To evaluate the prevalence and characteristics

of corneal astigmatism in senile cataract patients scheduled for cataract surgery

Methods Prospective study Institutional Review

Board approved January 2007-October

2009 Cataract surgery

candidates Inclusion criteria

Presence of cataract Age ≥ 40 years old

Exclusion criteria Corneal disease Irregular astigmatism Presence of pterygium Previous ocular

surgery Uncooperative patient

Methods Presurgical screening

examinations Keratometry (Topcon-

KR8100) Manifest refraction Best-corrected visual

acuity Slit-lamp examination Applanation tonometry Dilated fundus

examination

Statistical analyses STATA version 11 Mean, SD or median and

range Describing continuous

data Frequency and

percentage Describing categorized

data The level of significance

at P < 0.05

Results 2010 eyes in 1005 patients

Characteristic Value

Mean age (SD) (y) 68.21 (9.19)

Range of age (y) 42-96Gender (male/female) 388/ 617

Median value of corneal astigmatism (D) 0.88 (0-4.5)

Mean keratometry (D) - Steepest meridian - Flattest meridian

44.91 ± 1.5444.02 ± 1.56

Range of keratometry (D) 38-49

Prevalence of corneal astigmatism

Corneal Astigmatism (D)

Prevalence (%) 95%CI

≤0.5 20.97 17.31-25.01

>0.5-1 43.49 38.87-48.19>1-2 28.92 24.78-33.33

>2-3 5.30 3.42-7.78

>3 1.32 0.49-2.86

35.5% of the eyes had corneal astigmatism ≥ 1.25D

Corneal astigmatism in the age groups

Corneal cylinder in 4 age groups

0

10

20

30

40

50

<60 61-70 71-80 >80

Age group (years)

Freq

uenc

y (%

) ≤0.5 D

>0.5-1 D

>1-2 D

>2-3 D

>3 D

Corneal astigmatism increased with age (P <0.01)

Axis distribution

Axis distribution

ATR 62%

Oblique12%

WTR 26%

WTR

ATR

Oblique

[22.06-30.34][8.88-15.02]

[57.61-66.73]

Astigmatic axes in the age groups

Axis of astigmatism in 4 age groups

0102030405060708090

<60 61-70 71-80 >80

Age group (years)

Freq

uenc

y (%

)

WTR

ATR

Oblique

ATR astigmatism increased with age (P <0.001)

Discussion Attempted to determine the prevalence of

different amounts of corneal astigmatism A few such reports are available in the literature Prevalence of corneal astigmatism increased with

age, particularly ATR direction, similar to previous studies

Provide a useful information for cataract surgeon Several options for correcting corneal astigmatism

at the time of cataract surgery may be considered

Studies Ferrer-Blasco et al, 2009

Riley et al, 2001

Gonzalez et al, 2007

Present study, 2009

Eyes/ patients 4540/2415 502/488 N/A 2010/1005

Age 60.59±9.87 74.9±9.8 N/A 68.21±9.19

Sex 68.2% F 62% F N/A 61.37% F

Corneal astigmatism ≥ 1 D

34.8% N/A 63% 37.8%

Mean corneal astigmatism

0.90±0.93 0.9±0.80.75 (median)

N/A 1.05±0.620.88 (median)

Range of astigmatism

0.0-6.75 0.0-6.50 N/A 0.0-4.50

Axis of astigmatism N/A 50% ATR N/A 62% ATR

Mean steepest K (D) 44.08±1.61 44.1±1.7 N/A 44.91 ± 1.54

Range of K (D) 38-48 38.6-50.5 N/A 38-49

Conclusions The prevalence of corneal astigmatism > 1 D

was 35.5% in this study population Emphasize the importance of considering

preexisting corneal astigmatism in senile cataract patients prior to surgery to achieve the optimal postoperative refractive outcomes

Thank you for your attention