1 Reduction of ocular chromatic aberration by a blue light filtering intraocular lens Jim Schwiegerling, PhD Ophthalmology and Vision Science, The University of Arizona This study was funded by Alcon, which also assisted with preparation of this poster.

2 Introduction BECAUSE Longitudinal chromatic aberration makes eyes myopic focusing blue light, emmetropic focusing green light, and hyperopic focusing red light, 1 and Placing colored filters 2 or achromatizing optics 3 in front of the eye can improve contrast sensitivity THEREFORE Blue light filters in intraocular lenses (IOLs) might provide a visual benefit in reducing chromatic aberration PURPOSE To compare in vitro refractive error as a function of visible wavelength for a blue light filtering IOL versus a clear IOL 1. Thibos LN, Bradley A, Zhang XX. Effect of ocular chromatic aberration on monocular visual performance. Optom Vis Sci. 1991;68: Rieger G. Improvement of contrast sensitivity with yellow filter glasses. Can J Ophthalmol. 1992;27: Manzanera S, Piers P, Weeber H, Artal P. Visual benefit of the combined correction of spherical and chromatic aberrations. Invest Ophthalmol Vis Sci. 2007;48:1513.

3 Methods: Transmission Spectra Ultraviolet and visible transmission spectra were measured by placing AcrySof IOLs (Alcon Laboratories, Inc.) in a wet cell spectrophotometer system. Experimental design included: –a Perkin-Elmer Lambda 35 UV/Visible spectrophotometer, equipped with a Lab Sphere RSA-PE-20 integrating sphere –a quartz cell (CVI Laser, LLC Wavefront Sciences Quartz Cuvette) shaped as a rectangular cylinder (5 × 19.8 × 34.3 mm) contained a custom insert to hold the IOL filled with Balanced Salt Solution –3 transmission spectra per IOL, from 20 IOLs with 30.0 D power 10 IOLs that filtered ultraviolet light only (model SA60AT) 10 IOLs that filtered ultraviolet and blue light (model SN60AT)

4 Methods: Ocular Modeling The 50% transmission points of the averaged transmission spectra for each IOL were fitted to a well-established model of the “chromatic eye,” which shows the variation of refractive error of the human eye across the visible spectrum: “Chromatic eye” figure replotted from data in: Thibos LN, Ye M, Zhang X, Bradley A. The chromatic eye: a new reduced-eye model of ocular chromatic aberration in humans. Appl Opt. 1992;31: The “Chromatic Eye” Model

5 Results: Transmission Spectra 50% transmission at 409 nm 50% transmission at 458 nm

6 Results: Chromatic Refractive Error ( at 50% Transmission Wavelengths of IOLs) x = 409 nm (λ from SA60AT IOL) x = 458 nm (λ from SN60AT IOL) y = D y = D 0.75 D = difference between the 2 IOL models in effective ocular chromatic aberration “Chromatic eye” figure replotted from data in: Thibos LN, Ye M, Zhang X, Bradley A. The chromatic eye: a new reduced-eye model of ocular chromatic aberration in humans. Appl Opt. 1992;31:

7 Discussion: The Blue Filter in Context The blue light filtering chromophore was designed to protect the retina against phototoxicity mediated by blue light 1 Among wavelengths in the visible spectrum, blue light is most phototoxic 2 and the most strongly aberrated longitudinally (versus chromatic mean) 3 The correction of chromatic aberration reported in this study was due to the chromophore that was intended to protect the retina 1.Sparrow JR, Miller AS, Zhou J. Blue light-absorbing intraocular lens and retinal pigment epithelium protection in vitro. J Cataract Refract Surg. 2004;30: Sparrow JR, Nakanishi K, Parish CA. The lipofuscin fluorophore A2E mediates blue light-induced damage to retinal pigmented epithelial cells. Invest Ophthalmol Vis Sci. 2000;41: Thibos LN, Ye M, Zhang X, Bradley A. The chromatic eye: a new reduced-eye model of ocular chromatic aberration in humans. Appl Opt. 1992;31:

8 Conclusions The blue light filtering SN60AT IOLs reduced chromatic aberration in vitro (relative to the UV filtering SA60AT IOLs) by 0.75 D at the blue end of the visible spectrum

9 Acknowledgements The author thanks Xin Hong, PhD (of Alcon Research, Ltd., Fort Worth, TX) for providing source data.