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.
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8. Reduces contrast sensitivity and increases glare sensitivity… Spherical Aberration … especially at night when the pupil is large
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
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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.
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
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
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28. Object Detection: Tecnis ™ significantly better than control Data on file. AMO.
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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
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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
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35. Aspheric IOL Profiles Actual digital photos of 20D lens comparisons AMO AcrySof IQ IOL Equally powered AcrySof Natural IOL B&L
In ophthalmology and especially in cataract and refractive surgery the main objective is best quality of vision, but what does this mean - 20/20?
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.
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.
The spherical aberration of a natural human lens increases with age as is shown in this study by Glasser and Campbell.
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.
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.
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.
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.
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.
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.
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.
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).
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