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Purpose: To use optical modeling to compare a 6.0 mm and 7.0 mm intraocular lens (IOL) optic diameters on peripheral retinal illumination with implications for negative dysphotopsia. Setting: Mayo Clinic, Rochester, Minnesota, and Simpson Optics LLC, Arlington, Texas. Design: Model eye. Methods: Ray-tracing software was used to simulate retinal illumination from an extended light source for a pseudophakic eye with in-the-bag biconvex IOLs (refractive index [n] = 1.46 and 1.55) and a 2.5 mm pupil. Ray-tracing diagrams and simulated retina illumination profiles were compared using the 6.0 mm and 7.0 mm optic diameter IOLs. Retinal locations were scaled to relative visual angles from 70 to 110 degrees horizontally. Results: A 7.0 mm optic (n = 1.46) expands the image field by 2.8 degrees compared with a 6.0 mm optic. High-angle input light misses a 7.0 mmoptic at a larger visual angle than a 6.0 mm optic, shifting illumination of the peripheral retina by this light anteriorly by 5.6 degrees. Consequently, a region of nonilluminated peripheral nasal retina is enlarged and shifted peripherally using a 7.0 mm optic (visual angle, 86.3 to 96.3 degrees) compared with a 6.0 mm optic (visual angle, 83.5 to 90.7 degrees). Similar illumination changes were seen modeling a 1.55 n IOL. Conclusions: A narrow dark region in the nasal retina when using a 6.0 mm optic is changed to a broader, more peripheral dark region when using a 7.0 mm optic. An extended, more peripheral dark nasal region may make a temporal shadow less bothersome and explain lower negative dysphotopsia rates using a 7.0 mm optic. [ABSTRACT FROM AUTHOR]

To use ray-tracing analysis and simulated retinal illumination profiles to design an intraocular lens (IOL) that prevents or reduces negative dysphotopsia after cataract surgery. Mayo Clinic, Rochester, Minnesota, and Simpson Optics LLC, Arlington, Texas, USA. Experimental study. Ray-tracing software was used to simulate peripheral retina illumination from an extended light source for a pseudophakic eye with a biconvex high refractive index IOL. Ray intensities were adjusted to include the effects of the surface reflections and the energy reduction caused by pupil obliquity at high incident angles. The results were compared with similar optical modeling of a modified IOL design with a concave region on the peripheral posterior surface. For a standard biconvex high refractive index IOL, simulated retina illumination profiles showed an area of nonilluminated peripheral nasal retina at a relative visual angle of approximately 85 degrees to 93 degrees. Using a modified IOL optic with a peripheral concave posterior surface, ray-tracing diagrams showed that peripheral input rays were redirected anteriorly into the nonilluminated dark area of the peripheral retina. Simulated retina illumination images confirmed that the redirected input rays improved illumination to the peripheral retina, including the dark area. Optical modeling showed that the new IOL design provides more uniform illumination of the peripheral nasal retina and specifically illuminates the dark region of the nasal retina associated with negative dysphotopsia. This modified IOL design could prevent or reduce negative dysphotopsia after cataract surgery. [ABSTRACT FROM AUTHOR]