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Aspheric IOL’s: clinical benefits and customizing cataract surgery

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. Why a aspheric IOL ?. Aspheric lenses have been developped to:

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Aspheric IOL’s: clinical benefits and customizing cataract surgery

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  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 longitudinal spherical aberration paraxiale focus plain aspheric surface with negative Q

  4. Altitude datas in mm R0=R0=R0 7.78 mm Ri>R0 Q<0 Ri<R0 Q>0 Ri=R0 Q=0

  5. Corneal Radius in mm Q<0 Ri>R0 R0=R0=R0 7.78 mm Q=0 Ri=R0 Ri<R0 Q>0

  6. Tangential Refraction in D Q>0 Ri<R0 Ri=R0 Q=0 R0=R0=R0 7.78 mm Ri>R0 Q<0

  7. 3 3 3 3 Asphäre Q = +2.0 Sphäre Q = 0.0 2 2 2 2 1 1 1 1 F3 F2 F1 F3 F2 F1 1 1 1 1 2 2 2 2 3 3 3 3 F2 F1 F3 Asphäre Q = -2.0 Asphäre Q = -0.58 F1,2,3 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 Wavefront PSF MTF ideal real

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

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

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

  13. Eye and spherical aberrations As the natural lens ages, its structural change leads to an increase of +SA. This results in a loss of contrast sensitivity. 45 years 65 years 25 years Eye SA + Cornea Cornea Eye Cornea Human Lens Eye 0 Human Lens Human Lens SA -

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

  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)

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