Simulation of stray light with a phakic intraocular lens with a central hole

Abstract

AbstractPurpose Posterior chamber phakic intraocular lenses (pIOL) have been equipped with several holes to facilitate aqueous flow into the anterior chamber. The latest generation is equipped with a small hole in the center of the optic. The purpose of this study was to investigate whether a central cylindrical hole may increase intraocular stray light.Methods We established a hyperopic (+4 D) model eye in the ray tracing software ASAP based on the Liou Brennan model eye (LBME). A pIOL was placed between the iris and the crystalline lens with a central thickness of 0.25 mm. We created one pIOL model with and without central hole of 360 microns in diameter. Beams were projected to the eye at visual field angles up to 70° temporally. Intensity distribution was compared at retinal plane between the lens with and the lens without the hole.Results The pIOL model with central hole showed increased intraocular stray light at retinal plane originating from light sources in the peripheral visual field. When projecting light from a half visual field only, stray light is present in the entire visual field. However, intensity of stray light is rather small compared to direct rays. The pIOL without central hole showed stray light originating from interface reflections which are projected to retinal plane.Conclusion Stray light caused by the pIOL central hole showed a negligible effect on visual acuity in an ideal environment. However, glare in the peripheral visual field (e.g. traffic lights) might affect visual acuity due to an increase in intraocular stray light. Stray light caused by the central hole is more likely to appear in hyperopic eyes due to increased pIOL central thickness.