Aniseikonic Lenses and Driving

Hendrik P.Derksen, BSc.Optom.Holsboer Optometry, Arnhem, The Netherlands

Cornelis A. Verezen, BSc.Optom. FAAOErgra Low Vision, The Hague, The Netherlands

In this retrospective study

the effect on visual acuity of

binocular 9% aniseikonic spectacle lenses,

was investigated in subjects with

a borderline visual acuity

aiming to assist in keeping their drivers licence.

Dutch Requirements for Cardriving

• Binocular BCVA 0.5 or Monocular vision BCVA 0.6

• Unrestricted horizontal visual field 140°

• Normal dark/light adaptation

Aniseikonic lenses

Literature:

• First described by Ames, Gliddon & Ogle (1932)

• First use for the correction of severe cases of clinical Aniseikonia (Lancaster, 1932)

“Aniseikonia”visual defect in which the shape and size of an

ocular image differ in the two eyes

Lens Design (MultiLens® Sweden)

• Magnification 9%

• Average lens thickness 10 mm

• Curve 9 (inside > outside)

• Lensmaterial CR39

• Weigth 1 lens: ~ 30 gram

Inclusion criteria

• Possession of valid driving licence

• Binocular BCVA 0.3 (18/60) 0.5 (30/60)

• Visual status quo > 6 months

• No other obvious physical or mental disorder

• Strong wish to “pass the upcoming drivers test”

Methods

• Best corrected visual acuity (ETDRS)

• Contrast sensitivity function (CSV-1000 LV)

• Stereopsis (Titmus Randot)

• Visual field (Confrontation)

• Quality central field (Amsler)

Study setup (retrospective)

• 21 Subjects; Age:69 - 83 (mean 75.5);

• Primary reason for visual acuity loss: * AMD (dry form) in 12 subjects

* Cataract in 9 subjects

• Binocular BCVA: 0.33 (20/60) – 0.47 (28/60) (mean 0.39)

• CSF: 17.5 - 8.9 (mean 12.9)

• Stereopsis: 400” - 100” (mean 178.57”)

• No subjective metamorphopsia

Results 9% Aniseikonia

0,00

0,10

0,20

0,30

0,40

0,50

0,60

0,70

65 65 63 71 70 83 80 75 69 82 80 81 76 82 80 80 81 76 77 78 82 Age

VA

Va 9%

Va prior

Binocular 9% Magnification

21 Subjects 9% Aniseikonia

Binocular BCVA: 0.45 (27/60) – 0.65 (39/60) (mean 0.51)

CSF: 8.9 - 6.3 (mean 8.03)

Stereopsis: 250” - 70” (mean 123.80”)

9% magnification

• Improvement of VA from below to above legal requirement level ( 0.5 (30/60)) in all 21 subjects

• 12 Subjects succeded to pass the driving test

• 3 Subjects did not execute the medical exam for different reasons (costs and/or negative advise of family)

Results

• For individuals with borderline visual acuity, fitting 9% aniseikonic lenses is a promising option to pass the medical exam for a driving licence in the Netherlands

• Aniseikonic lenses should be considered in selected patients to enhance visual acuity

• The use of aniseikonic lenses fitted binocular in order to enhance visual acuity for driving deserves further research

Conclusion

Thank you

for your kind attention