Analysis of edge glare phenomena in intraocular lens edge designs

Purpose: To determine the image and relative intensity of reflected glare i mages from 4 commonly used intraocular lens (IOL) edge designs to assess th e potential for noticeable postoperative edge glare. Setting: University of Texas Medical School, Houston, Texas, USA. Methods: The interaction of light rays from 4 common IOL edge designs were examined in an eye model using the OptiCAD 3-D radiometric ray-tracing prog ram (Opticad : Corp.). Comparison of the potential of the 4 edge designs to produce visual sensations was derived from plots of the spatial location a nd energy distribution of rays forming the retinal image. Results: Edge designs with no anterior and posterior dioptric powers at the lens periphery (lenticular) and rounded corners distributed the edge glare rays over a large retinal area. Edge designs with sharp edges formed by "c ropping" the anterior and posterior optic zones focused edge glare rays int o distinct are-shaped images. The peak intensity of the are-shaped image wa s 8 to 10 limes stronger than the peak intensity of the diffuse image forme d by lenses with rounded edges. Conclusions: Rounded IOL edges distribute reflected glare image over a sign ificantly greater area than sharp edges. Rounded edges reduce the potential for edge glare phenomena that appear to the patient as a thin crescent or partial ring. J Cataract Refract Surg 1999; 25:748-752 (C) 1999 ASCRS and E SCRS.