Aspheric IOLs for CRGH
- 1. What’s all this talk about aspheric IOLs? Con Moshegov Dept of Ophthalmology Meeting CRGH October 2, 2007.
- 2. Cataract surgery: patient expectations Whether implanted with monofocal or multifocal IOLs patients can have problems with the quality of vision Poor vision at night, glare, halos, dysphotopsias not to mention gripes independent of the IOL choice IOL technology has improved to maximise quality of vision Many surgeons prefer to keep things just as they are
- 3. 20/20 ? Quality of Vision?
- 4. Contrast Sensitivity is a better test of functional vision than Visual Acuity!
- 5. Sinewave contrast sensitivity is the most widely accepted test of contrast sensitivity It is more specific and sensitive than ETDRS, Pelli-Robson tests
- 6. Contrast Sensitivity The more cycles per degree the patient can see the better the contrast sensitivity.
- 7. Many things reduce contrast sensitivity Optical error Lower order aberrations: sphere and cylinder Higher order aberrations: not correctable with glasses Ocular pathology Age (Possibly) cataract surgery
- 8. Reduces contrast sensitivity and increases glare sensitivity… Spherical Aberration … especially at night when the pupil is large
- 10. Wavefront Aberrometry Provides a description of the entire optical error of the eye
- 11. Spherical lenses do not focus parallel light rays exactly on one point. Positive spherical aberration results when the refractive power in the periphery is too strong. Negative spherical aberration results when the refractive power in the periphery is too weak. The resulting image is less clear and has less contrast Spherical Aberration Negative Spherical Aberration Positive Spherical Aberration
- 12. Spherical aberration of the cornea positive spherical aberration
- 13. The cornea of a young eye has positive spherical aberration which is neutralised by the negative spherical aberration of the lens. The Young Eye Spherical Aberration in Human Eyes
- 14. Healthy subjects from 20 to 70 years of age. Overall aberrations increase by a factor of 3 with age. Corneal aberrations change only moderately. Applies to all higher-order aberrations such as coma, trefoil etc Artal, Berrio, Guirao, Piers (2002) J.Opt.Soc.Am.A.Opt.Image Sci.Vis. 19(11): 137-143 Changes over a lifetime
- 15. Wavefront Aberrations of the Eye Increase with Age Guirao A, Artal P. Corneal wave aberration from videokeratography: accuracy and limitations of the procedure. J Opt Soc Am A Opt Image Sci Vis. 2000;17:955-65.
- 16. Wavefront Aberrations of the Cornea Remain Relatively Constant with Age Guirao A, Artal P. Corneal wave aberration from videokeratography: accuracy and limitations of the procedure. J Opt Soc Am A Opt Image Sci Vis. 2000;17:955-65.
- 17. Spherical Aberration of the Natural Human Lens Glasser A, Campbell MC. Vision Res. 1998;38:209-29.
- 18. Contrast Sensitivity Decreases with Age
- 19. Aging of the lens Young Old “ The lens grows over a lifetime - and in doing so, changes its curvature. ”(Brown, 1974) “ The Lens becomes thicker …” (Koretz et al, 1989) “ The refractive index of the lens changes …” (Smith et al, 1992)
- 20. Spherical Aberrations in Human Eyes The positive spherical aberration of the mature cornea is no longer neutralised as the lens also has a positive spherical aberration. The Mature Eye
- 21. Standard IOLs increase aberrations Aberrations of cornea and standard IOLs
- 23. Conventional IOLs Tecnis T E C N I S Z-SHARP OPTIC TECHNOLOGY A New IOL for Better Vision!
- 24. Total Spherical Aberration 1 and 3 months after surgery -0.04 -0.02 0 0.02 0.04 0.06 0.08 0.1 0.12 1 month 3 months Z(4,0) µ m SI40 Tecnis™ Mester et al. Impact of a modified optic design on visual function: Clinical comparative study. J Cataract Refract Surg. 2003; 29:652–660
- 25. Photopic Contrast Sensitivity 3 months after surgery Mester et al. Impact of a modified optic design on visual function: Clinical comparative study. J Cataract Refract Surg. 2003; 29:652–660 * * * * * Spatial frequency (c/deg) contrast sensitivity 0 10 20 30 40 50 60 70 80 90 100 1.5 3 6 12 18 * P < 0.05 Tecnis™ SI40
- 26. Mesopic Contrast Sensitivity 3 months after surgery Mester et al. Impact of a modified optic design on visual function: Clinical comparative study. J Cataract Refract Surg. 2003; 29:652–660 * * * * * 0 10 20 30 40 50 60 70 80 90 * P < 0.05 Tecnis™ SI40 Spatial frequency (c/deg) Contrast sensitivity 1.5 3 6 12 18
- 27. Night Driving Simulation Long straight street Simulated speed 35 miles/h High degree of ambient light Long straight road Simulated speed 55 miles/h Minimum ambient light (low beam auto headlights) City Driving Scene Rural Driving Scene Target detection and identification
- 28. Object Detection: Tecnis ™ significantly better than control Data on file. AMO.
- 29. Night Driving Simulation With Tecnis ™ and at 55 mph, patients identify a pedestrian (rural setting/glare) at 486 feet versus 441 feet for the standard IOL (p=0.0011) Increased reaction time Safer stopping Data used in FDA submission for recognition of special status
- 30. Improved functional vision with a modified prolate intraocular lens . Packer M, Fine IH, Hoffman RS, Piers PA. J Cataract Refract Surg. 2004 May;30(5):986-92. Methods: Patients randomly assigned to receive a Tecnis Z9000 IOL (Pfizer) or a Sensar OptiEdge AR40e IOL (AMO) in 1 eye were followed for 3 months postoperatively Conclusion: Results show the Tecnis IOL with a modified prolate anterior surface produces better contrast sensitivity than a standard spherical IOL under mesopic and photopic conditions. 15 Patients per group/ 3 months follow up TECNIS Z9000 Studies
- 31. AcrySof IQ (SN60WF) IOL Tecnis Z9000 IOL B&L LI61AO/AOV IOL Source: Package Inserts, Data on File Adds -0.20 µm spherical aberration. Adds -0.27 µm spherical aberration. Adds 0.00 µm spherical aberration.
- 32. Aspheric IOLs a Laboratory data on file. Alcon Laboratories, Inc. b Holladay et al., A new intraocular lens design to reduce spherical aberration of pseudophakic eyes. JCRS 2002; 18:683-691. c Mester et al., Impact of a modified optic design on visual function: clinical comparative study. JCRS 2003; 29:652-660. d Altmann et al., Optical performance of 3 intraocular lens designs in the presence of decentration. JCRS 2005; 31:574-585. ~ 0.28 d 0.00 d SofPort AO ~ 0.00 c − 0.27 b Tecnis ~0.1 a − 0.20 a AcrySof IQ Overall Spherical Aberration ( µ m) Lens Spherical Aberration ( µ m) 6.0 mm Pupil Size
- 33. Residual Spherical Aberration Figures in µm SA Lens Cornea 1. Artal et al. Journal of Vision 2001; 1:1-8. 2. Levy et al. AJO 2005; 139:225-228. 3. Legras R , Chateau N, Charman WN. Assesment of Just-noticeable differences for refractive errors and spherical aberration using visual stimulation. Opt Vis Science (81)9 718-728. 4. Glasser A , Campbell MCW. Vision Res 1998; 38:209–229 5. Holladay et al. J of Refract Surg 2002; 18:683-691. 6. Wang L ,, et al. Higher order aberrations from the internal optics of the eye. JCRS 2005;31. 65 yrs 20 yrs AcrySof IQ AO / AOV Tecnis +0.074 +0.275 0.0 -0.200 0 -0.274 0.274 0.274 0.274 +0.174 +0.094 -0.100 -0.180 0.274 0.274
- 34. AcrySof ® IQ (SN60WF) Material: AcrySof® with UV and blue light-filtering chromophores Haptic Type: STABLEFORCE® Modified-L Optic Diameter: 6.0 mm Overall Length: 13.0 mm Refractive Index: 1.55 Special Feature: Posterior Aspheric Surface Diopter Range: +6.0D to +30.0D A-Constant: 118.7
- 35. Aspheric IOL Profiles Actual digital photos of 20D lens comparisons AMO AcrySof IQ IOL Equally powered AcrySof Natural IOL B&L
- 36. AcrySof IQ SN60WF - New Clinical Data* Controlled, randomized, double-masked, multicenter contralateral implant study of the AcrySof® IQ IOL versus a spherical control lens demonstrated the following: Ocular spherical aberrations statistically significantly less in AcrySof® IQ eyes vs. the control lens (SA60AT). Statistically significant improvement in contrast sensitivity in eyes implanted with the AcrySof® IQ lens vs. control. Functional vision improvement statistically significant based on simulated night driving, vs. control, especially in glare and fog. *FDA Approval in U.S. for New Clinical Data Claims for AcrySof IQ SN60WF IOL vs. monofocal spherical control lens. (April 2007)
- 37. Clinical patient benefits: S N60WF (IQ) vs. SA/SNAT Better Contrast Less spherical aberration
- 38. IOL models with asphericity are multiplying B&L Acryos B&L Sofport B&L MIL60 AMO Tecnis (silicone) AMO Tecnis Acrylic AMO Tecnis CL Alcon IQ
- 40. What if? The IOL is tilted? The IOL is decentred? The SE is wrong?
- 41. Tilting
- 42. Ammetropia
- 43. Ammetropia Glasses will still give better vision than with a standard IOL
- 44. Conclusions IOL technology is getting better and translates into practically significant improvements in vision Aspheric IOLs give most patients a chance at better vision Many CRGH patients could benefit from aspheric IOLs Optimal results would be achieved if we paid more attention to: Pre-operative biometry IOL calculation formulae Phaco techniques Attention to refractive outcomes
Editor's Notes
- #4: In ophthalmology and especially in cataract and refractive surgery the main objective is best quality of vision, but what does this mean - 20/20?
- #16: 1 Total wavefront aberrations of a number of human eyes are plotted in this figure as a function of age. Despite the inter-subject variability, the wavefront aberrations of the eye increase with age.
- #17: 1 In this figure you can see the total wavefront aberrations of the cornea for every subject. The corneal aberrations remain relatively constant with age.
- #18: The spherical aberration of a natural human lens increases with age as is shown in this study by Glasser and Campbell.
- #19: As we get older, we lose contrast sensitivity, first at the higher spatial frequencies, then for all the spatial frequencies. Our patients need regular checkups that include contrast sensitivity testing to monitor and assess the changes in their vision.
- #26: Average Photopic Contrast Sensitivity Values— 3 Months postopereatively Measurement of the photopic contrast sensitivity, or contrast sensitivity under high light conditions, showed that the patients with the Tecnis ™ lens had higher contrast sensitivity. This means that the patients detected objects of lower contrast better with the eye implanted with the Tecnis ™ lens than with the eye implanted with the SI40 lens.
- #27: Average Mesopic Contrast Sensitivity Values— 3 Months postopereatively Measurement of the mesopic contrast sensitivity, or contrast sensitivity under low light conditions, showed that the patients with the Tecnis ™ lens had higher contrast sensitivity. This means that the patients detected objects of lower contrast better with the eye implanted with the Tecnis ™ lens than with the eye implanted with the SI40 lens.
- #28: MESSAGE: We used the NDS system designed by Dr. Ginsburg. This system was validated against detection and identification distances from published Dept. of Transportation Data. Ginsburg A, Kelly M; Functional vision testing: night driving simulator studies (1995) ASCRS ASOA Symposium of Cataract, IOL and Refractive Surgery, San Diego, California, April 1-5, 1995.
- #29: MESSAGE: The tallest the bar the greater the diff in detect distance Z9000 is superior to SA60AT in detection of most of the targets under various conditions. Greatest advantage seen for hazard target (pedestrian) under rural (lower light) conditions. Pedestrian target is less defined than a road sign (highly reflective surface, high contrast letters/figures). Suggesting that Z9000 is superior especially for low contrast targets under low illumination.
- #32: B&L LI61AO-V (Violet Shield) lens has only a higher concentration of the original UV chromophore in the LI61A0 lens aberration-free IOL. The additional chromophore provides only 10 nm additional UV blockage (from 400nm to 410nm). See next slide for LI61AO DFU light transmission curves for A0 and AO-V models.
- #34: Key takeaway from this slide information: AcrySof IQ compensates for the corneal positive spherical aberration (SA) (SA of cornea is basically stable with aging), and the IQ negative spherical aberration lens design is more similar to what is found in youthful eyes that create this same affect for compensation of the corneal positive SA. Studies by Li Wang and Doug Koch (REF. 6. and detailed on Slide 9 is the support). AcrySof IQ compares more closely to the residual positive spherical aberration found in youthful eyes. This provides for a more natural improvement in image quality for patient vision.
- #36: Images: top = AcrySof IQ (20D) middle = Tecnis Z9000 (20D silicone 3-piece) bottom = B&L LI61AO (20D silicone 3-piece) Sidenote: AcrySof IQ can be inserted through a 2.3 mm post-implantation incision using the MONARCH II C-Cartridge, and microcoaxial phaco surgery technique using the Infiniti System. (ESCRS 2005 Live Surgery with Khiun Tjia, MD/Zwolle, Netherlands).