1. Aspheric IOL’s: clinical benefits and customizing cataract surgery Bojan Pajic, MD, PhD, FEBO Swiss Eye Research Foundation, ORASIS, Reinach, Switzerland Division of Ophthalmology, University Hospitals of Geneva, Switzerland

2. Why a aspheric IOL ? Aspheric lenses have been developped to:  Reduce spherical aberration in the eye  Increase contrast sensitivity

3. spheric surface aspheric surface with negative Q longitudinal spherical aberration paraxiale focus plain

4. Q<0 Q>0 Q=0 R 0 =R 0 =R 0 7.78 mm R i >R 0 R i <R 0 R i =R 0 Altitude datas in mm

5. Corneal Radius in mm R 0 =R 0 =R 0 7.78 mm R i >R 0 Q<0 Q=0R i =R 0 Q>0 R i <R 0

6. Tangential Refraction in D R 0 =R 0 =R 0 7.78 mm R i >R 0 Q<0 Q=0 R i =R 0 Q>0R i <R 0

7. 1 2 3 1 2 3 F1F1 F2F2 F3F3 F1F1 F2F2 F3F3 F3F3 F2F2 F1F1 F 1,2,3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 Sphäre Q = 0.0 Asphäre Q = -0.58 Asphäre Q = +2.0 Asphäre Q = -2.0 Schematic comparison of different longitudinale aspherical aberrations

8. Spherical Aberrations Higher order aberration Zernike Level 4 : Z4.0 The retinal image is no more a clear point but a circular spot made of concentric circles

9. Comparison of geometric shapes Spherical IOL MTF ideal real Wavefront PSF

10. Comparison of geometric shapes Ideal Apherical IOL Wavefront PSF MTF ideal real

11. Aspheric of Cornea, IOL, Cornea + IOL CorneaIOLCornea + IOL

12. Eye and spherical aberration The cornea induces +SA Mean value +0.274 µ The young human lens induces -SA Mean Value -0.138 µ The young eye has a physiological moderate amount of +SA which contributes to quality of vision (depth of field) Mean Net Balance +0.136 µ

13. Eye and spherical aberrations SA + SA - 0 25 years 45 years65 years Cornea Human Lens Eye As the natural lens ages, its structural change leads to an increase of +SA. This results in a loss of contrast sensitivity.

14. -2.0-1.5-0.50.00.51.0 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 spherical IOL aspherical IOL (fix. Q-value for all IOL's) aspherical IOL with custumize Q-value spherical aberration Corneal asperical Q-value Spherical aberration of the whole eye

15. Study Spherical and Aspheric lenses comparision:  PhysIOL H65CN  PhysIOL Poly A 123  Tecnis 1 AMO

16. Sperical aberration measured

17. Mesopic Contrast Sensitivity

18. Photopic Contrast Sensitivity

19. Conclusions – Apheric IOL Benefits :  Improvement in contrast sensitivity  Better comfort of vision, especially in low light conditions (mesopic vision, large pupil diameter (mydriasis))  Tend to reproduce the optical system of the young eye

20. Conclusions – Apheric IOL Limits :  Necessitate a perfect position in the eye (Induce other types of aberration (such as coma) in case of tilt or decentration)  Cannot be used if the cornea has –SA (refractive surgery)