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IOL Selection- What to Ask and What to Tell Patients
- 1. IOL Selection What toAsk and What to Tell Dr. Inderjit Singh FRCS(London),FRCOPTH ,FRANZCO Chatswood Eye Centre Suite 5, 16-18 Malvern Av, Chatswood Tel 94114877 1
- 2. IOL what toask What is your Ultimate Goal • 72yr old very fit lady with visually significant cataracts – surgery discussed, straight forward consult for cataract surgery and IOL to improve visual function • but pt also mentions that she travels frequently, • And her next trip =
- 3. CATARACT SURGERY- THE CONVERGENCE •The pt’s visual goal • The surgeon’s expertise with technique and use of IOLS – need a variety of IOLs, one fits all not possible; • Predictable results = <2.2mm astigmatic neutral incision; consistent round central capsulorhexis for consistent central IOL position • The technology – improvements of IOL design. Better understanding of visual optics
- 4. The Best IOLchoice for outcomes and pt satisfaction Visual quality- all about vision with good contrast Pts expectations and pt selection (co morbidities) Pts visual needs IOL technology that can deliver above – keep up with IOL technology Surgeons experience with IOL technology Pt selection - every pt is different – not a cookie cutter answer; pts near and intermediate va can differ - mobile phone, book, computer screen,dashboard Neural adaptation - visual cortex has to adapt to multifocal IOLs or monovision Binocular summation- 2 eyes with good distance vision have 40% better binocular contrast sesitivity compared to monocular vision
- 5. Choosing an IOLwhat to ask • Mary 72 yr- needle work without glasses,happy to wear glasses for distance • Fred 69yr-car enthusiast loves driving , wants to see as well as possible at night • Jack 55yr- keen golfer/ surfer- wants distance and some near vision, glasses for reading • Esther 68yr- traveller camper hiker near and distance vision without glasses
- 6. AGEING EYES, CHANGINGVISIONAGEING EYES, CHANGING VISION Increased ocular densities Blue end of visible spectrum filtered out Older lens absorbs 1000x>at 400nm Increased higher order aberrations Scatter due to cataract formation causing glare disability (? MVA) Decreased cone sensitivity-25% for each decade starting at adolescence Neural losses
- 7. The Ageing Eye ForGlasses free high quality vision vision = Removal of cataract +correction of aberrations of the eye • Lower order aberrations • Higher order aberrations Distortion of wavefront of light when it passes through eye with irregularities of its refractive components- tear film,cornea,lens
- 8. Visual Function Test-VF7Visual Function Test- VF7 •Reading signs – traffic,street,store •Seeing steps,stairs,or curbs •Watching TV •Night driving •Reading small print •Doing fine handiwork •Cooking
- 9. Lower order aberrations havefamiliar names • Myopia Astigmatism-87%ofcat pt • 33 • Hypermetropia
- 10. Proper technique hasadvantages over Femtosec laser assisted cataract surgery Correction of lower order aberrations
- 11. Higher Order Aberrations sphericalAberration is the most prevalent HOA in humans •Higher-order aberrations comprise many varieties of aberrations. Some of them have names such as coma, trefoil and spherical aberration, but many more of them are identified only by mathematical expressions (Zernike polynomials). They make up about 15 percent of the total number of aberrations in an eye. •Order refers to the complexity of the shape of the wavefront emerging through the pupil — the more complex the shape, the higher the order of aberration.
- 12. Light ScatterLight Scatter EarlierCataract Operations(4)Earlier Cataract Operations(4) There are two kinds of light—the glow thatThere are two kinds of light—the glow that illuminates and the glare that obscures.illuminates and the glare that obscures. James ThurberJames Thurber
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- 14. The ageing eye-spherical aberration Increased higher order aberrations- mainly 3rd – coma 4th order- spherical aberration If an aberration can be measured it can be corrected Positive spherical aberration is produced when peripheral rays deviate and cross in front of the retinal plane.
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- 16. Spherical aberration withage as lens ages its positive aberration increases and total optical system aberration increases ; contrast decreases; PUPIL DEPENDENT the fix = use aspherical IOL The crystalline lens before age 20 (in blue) generates little SA due to a flat anterior surface and thin optic. Beyond age 20 (in red), the anterior surface becomes more spherical (oblate) and induces increasing amounts of SA
- 17. • Using asphericIOL improves driving particularly evident on nighttime simulation testing, in which up to a 45-foot advantage in stopping distance at 55 mph (88.51 km/hr) can be achieved.
- 18. Different IOLs canbe used to offset different amounts of spherical aberration
- 19. Refractive cataract surgery 1.Restoretransparency of ocular media i.e remove opaque lens 2.Accurately correct any refractive aberrations of the eye - myopia,hyperopia 3.Correct astigmatism 4.Reduce spec dependence 5. 1+2+3+4 = predictable stable visual outcome 6.WHAT ABOUT NEAR VISION
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- 21. What To Tell MultifocalIOLs – we have the technology to somewhat turn the clock back ! Spectacle free distance and near vision •94% spectacles free (3 mnths) •6% used glasses for specific dim light tasks •8% c/o visual disturbances in the 1st week. •40% noticed some visual symptoms when asked – not intolerable •None of the symptoms were severe enough to explant IOL •All of pts would recommend IOL
- 22. WHAT TO TELL– more important to tell THE DISADVANTAGES OF MULTIFOCALS • All MF have some optical disadvantages • Light entering the eye through a MF is split into more then one focal point • Halos , glare, decreased contrast sensitivity at night,negative and positive dysphotopsia • MF not suitable for night drivers • Pt with any other ocular comorbidities will notice these more readily – dry eye,AMD • Intermediate distance va (computer) poor
- 24. What To Tell TheNew Multifocal Family- “Multifocal Light” for the active elderly • Good distance va • Less halos,glare • Contrast sensitivity effected less • Intermediate distance va better • Still have acceptable near va • But need glasses for reading fine print • Oculentis comfort ReStore +2.5 • Zeiss Lisa Trifocal
- 25. Multifocal “Light” Refractive Diffractive(ReStor +2.5) ; Bifocal (Oculentis Comfort) • 50 pts=57-87yrs(65-87) • All wanted to spectacle free for distance ,driving,golf,sailing,touring • Wanted some reading vision (computer work) , willing to wear glasses for fine print reading • UCDVA= 6/9-6/4(94%6/6 or better) • UCNVA= N8-N5 (44%N8) • All were Toric IOLs except 8 eyes • 10% noticed visual disturbance in 1st week • 6% noticed halos,glare (at night) but not intolerable • No explants
- 26. What To Tell– Contraindications of Multifocal IOL s Ocular Co Morbidities • Dry eye condition • AMD- wet or dry or pre AMD (drusen) • Diabetic macular oedema and retinopathy • Irregular astigmatism • Previous corneal surgery (Lasik)
- 27. ACRYSOF ReSTOR +2.5 •50 pts=57-87yrs(65-87) • All wanted to spectacle free for distance ,driving,golf,sailing,touring • Wanted some reading vision (computer work) , willing to wear glasses for fine print reading • UCDVA= 6/9-6/4(94%6/6 or better) • UCNVA= N8-N5 (44%N8) • All were Toric IOLs except 2 eyes • 10% noticed visual disturbance in 1st week • 8% noticed halos,glare (at night) but not intolerable • No explants
- 28. Continual quest forhigh quality correction Ophthalmologists and their patients are continually striving for high quality vision correction. Perhaps the television industry and Apple has set the bar even higher with the successful introduction of HDTV and retinal image IPad, which has verified patients’ (and their visual cortex’s) strong desire for a level of correction beyond lower order sphere and cylinder. This patient desire along with the increasing role of wavefront science in vision and eye care have produced a growing understanding and clinical awareness of the role of HOAs, specifically fourth order SA and its relationship to the pupil. SA is the most prevalent HOA in human vision and thus must be addressed in any efforts toward high quality vision correction. Its objective magnitude and subjective effects on vision are directly related to pupil diameter and, thus, that relationship must be addressed in the measurement and correction of SA. While such measurements have been effectively achieved and will continue to advance through the ever increasing sophistication of wavefront aberrometry, the correction of SA and its relationship to the pupil will present unique challenges, some of which have already been addressed with developing
- 29. Continual Quest forhigh quality vision by Ophthalomolgist and the patient • Perphaps introduction of HDTV ,iPad with retina display are setting the bar even higher for vision correction • This has verified pts (and their visual cortex) strong desire for correction beyond lower order sphere and cylinder • Increasing role of wavefront science in identifying HOAs that can be corrected (SA) to achieve high quality vision. • This playing increasing part in IOL design and use
- 30. Cataract Surgery WithImplantation of an Artificial Lens Thomas Kohnen, Prof. Dr. med.,1,2,* Martin Baumeister, Dr. med.,1 Daniel Kook, Dr. med.,3 Oliver K. Klaproth, Dipl.-Ing. (FH),1 and Christian Ohrloff, Prof. Dr. med. • The main criterion for the success of cataract surgery, aside for an uncomplicated course of the procedure itself, is the long-term visual result. The most commonly evaluated endpoints are high-contrast visual acuity and the residual refraction deficit at the visual distances for which the implanted lens is intended (6, 21). The expression “quality of vision” has been coined in view of the fact that high-contrast visual acuity, though it can be measured simply and quickly, is not a fully adequate measure of the complex phenomenon of visual perception (e33, e34). Quality of vision is the patient’s ability to see well in the context of his or her own individual visual requirements (e35). Various objective and subjective measures are used to determine the quality of vision (6, 22).
Editor's Notes
- #7 Higher order aberration=negative lens aberration to compensate for positive spherical aberration of cornea
- #12 More then 60 shapes or aberrations have been identified with larger pupil sizes generally may have more problems with vision symptoms caused by higher-order aberrations, particularly in low lighting conditions when the pupil opens even wider.
- #14 Higher order aberrations were calculated from the Zernike polynomials up to the 4th order. The amount of light scatter was estimated by using the diameter of the point spread functions (PSFs) of the Hartmann images.
- #16 Average Value is 0.27um with standard deviation of 0.1um he total higher-order aberrations of the phakic eye are composed of aberrations arising from the anterior corneal surface, the posterior corneal surface, the crystalline lens and the retina. In the aphakic eye, however, 98.2 percent of the aberrations arise from the anterior corneal surface.8 As this discussion is about pseudophakia, then necessarily the corneal aberrations are of importance, and for our purposes, can be thought of being representative of the whole aphakic eye. - See more at:
- #21 Refraction is the change in direction of a wave due to a change in its transmission medium. Diffraction is The process by which a beam of light or other system of waves is spread out as a result of passing through a narrow aperture or across an edge, typically accompanied by interference between the wave forms produced.