1. Aniseikonic Lenses and Driving Hendrik P.Derksen, BSc.Optom. Holsboer Optometry, Arnhem, The Netherlands Cornelis A. Verezen, BSc.Optom. FAAO Ergra Low Vision, The Hague, The Netherlands

4. 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.

5. Dutch Requirements for Cardriving Binocular BCVA  0.5 or Monocular vision BCVA  0.6 Unrestricted horizontal visual field  140° Normal dark/light adaptation

6. 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

8. Lens Design (MultiLens ® Sweden) Magnification 9% Average lens thickness 10 mm Curve 9 (inside > outside) Lensmaterial CR39 Weigth 1 lens: ~ 30 gram

9. 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”

10. Methods Best corrected visual acuity (ETDRS) Contrast sensitivity function (CSV-1000 LV) Stereopsis (Titmus Randot) Visual field (Confrontation) Quality central field (Amsler)

11. 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

13. 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”)

14. 9% magnification

15. 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

16. 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

17. Thank you for your kind attention