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Multifocal Intraocular Lenses & Contrast Sensitivity

Multifocal Intraocular Lenses & Contrast Sensitivity. Dr Kerrie Meades MBBS(Hons) FRANZCO FRACS Cataract and Refractive Surgeon. Multifocal IOL’s. Come in three basic types; Refractive Diffractive Accommodative Multifocal IOL’s can also be Aspheric & contain a UV or blue filter.

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Multifocal Intraocular Lenses & Contrast Sensitivity

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  1. Multifocal Intraocular Lenses & Contrast Sensitivity Dr Kerrie Meades MBBS(Hons) FRANZCO FRACS Cataract and Refractive Surgeon

  2. Multifocal IOL’s Come in three basic types; • Refractive • Diffractive • Accommodative Multifocal IOL’s can also be Aspheric & contain a UV or blue filter

  3. Aspheric IOL’s • The idea of the aspheric IOL is to return the eye to that of youthful optics, The young eye has zero Spherical Aberration • With age, Spherical Aberration increases reducing functional vision

  4. Filters – Blue light & UV • The human lens has the ability to filter UV and blue light naturally • Blue light filtration (yellow) & UV blocking is believed to slow down the progression of AMD caused by exposure • virtually 100% of IOL's now contain UV-absorbers

  5. Multifocal IOL’s • Multifocal IOL’s provide greater spectacle independence to patients • Careful patient counseling is needed to match a lens solution to the patients expectations. • Sometimes you may need to Mix IOL’s to suit a patients visual requirements.

  6. Refractive • Refractive multifocal IOL’s are designed with several optical zones on the IOL. • These zones provide various focal points, allowing for an improvement in distance, intermediate, & near vision • Rezoom offers a good DVA. Mid-distance haloing is a side effect

  7. Diffractive Restor • Diffractive multifocal IOL’s have gradual diffractive steps on the IOL implant that create a smooth transition between focal points. • The IOL also bends incoming light to the multiple focal points to increase vision in various lighting situations. • Haloing is a side effect Tecnis

  8. Tetraflex Accommodative • An accommodative IOL only has one focal point, but the focal point moves • The IOL has a hinge similar to the mechanics of the eye’s natural lens. • Using the eye’s muscles, the single focal point of an accommodative IOL can shift to bring objects at varying distances into focus • Patients get good DVA but NVA may be variable • No Haloing crystalens 5-0

  9. Patient Experiences with Restor +3 • JW 68years • Pre-op RVA 6/12 LVA 6/6 • R +1.25/+1.00x36 L +1.25/+0.75X36 • Both IOL’s implanted Sept 2008 • Patients vision 6/6, N5 each eye • Patient very happy with vision and overall performance of IOL especially at intermediate distances

  10. Contrast Sensitivity • Contrast sensitivity is the visual ability to see objects that may not be outlined clearly or that do not stand out from their background. • The ability to see a shade of gray on a white background or to see white on a light gray background declines with age.

  11. People with Low Contrast Sensitivity can suffer from the following: • Trouble seeing traffic lights or cars at night • Not being able to see spots on clothes, counters, or dishes • Not seeing whether a flame is burning on a stove • Needing a great deal of light to read • Experiencing tired eyes while watching television.

  12. Tecnis Multifocal IOL • The diffractive Tecnis ® ZM900 multifocal intraocular lens (AMO) provides good near visual acuity & good contrast sensitivity atall distances • Patients receiving the Tecnis multifocal IOL had better near visual acuity and better contrast sensitivity at all distancescompared to implantation with the refractive ReZoom™ multifocal IOL (AMO),

  13. AcrySof® ReSTOR® IOL • There is no clinical or functional significant difference between the contrast sensitivity of AcrySof® ReSTOR® and monofocal control subjects at lower spatial frequencies • Lower spatial frequencies are important for vision related to everyday life skills, such as walking, driving and reading.

  14. AcrySof® ReSTOR® IOLBinocular Mesopic Contrast Sensitivity Clinical Significance  0.3 log units at 2 or more Spatial Frequencies

  15. AcrySof® ReSTOR® IOLBinocular Photopic Contrast Sensitivity Clinical Significance  0.3 log units at 2 or more Spatial Frequencies

  16. Contrast Sensitivity • The following 2 slides clearly show very little difference between Contrast Sensivity in a Multifocal IOL vs a Monofocal IOL • It is also clear that Contrast Sensitivity in photopic conditions varies only slightly to the Contrast Sensitivity obtained in mesopic conditions for either style of lens

  17. AcrySof® ReSTOR® IOLMonocular Contrast Sensitivity Mesopic Conditions - With Glare Clinical Significance  0.3 log units at 2 or more Spatial Frequencies

  18. AcrySof® ReSTOR® IOLMonocular Contrast Sensitivity Photopic Conditions - No Glare Clinical Significance  0.3 log units at 2 or more Spatial Frequencies

  19. Acri.LISA Multifocal • Due to asymmetrical light distribution Acri.LISA IOLs achieve a high light yield. • The optical performance under mesopic conditions differs only slightly from photopic conditions. • The contrast sensitivity is improved to a level which is within the normal range for healthy phakic patients.

  20. Thank you

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