We performed two tissue culture experiments designed to compare the effects of various posterior chamber optics on lens epithelium. In the first experiment, we recorded, by phase contrast microphotography, the migration of rabbit lens epithelium exoplants placed adjacent to the optic of various posterior chamber lenses. In the second experiment, we used phase contrast microphotographs to document the effects of various posterior chamber optics when gently placed on a confluent layer of rabbit lens epithelium. From our in vitro studies, we conclude the following: There is inhibition of lens epithelial migration and even cytotoxic effects from direct contact with polymethylmethacrylate optics; glass optics have appreciably less effect on lens epithelium; polymethylmethacrylate optics with ridges (complete annulus or incomplete) do not inhibit lens epithelial migration as well as planoconvex lenses, and they do not have a cytotoxic effect except at the points of contact between the ridge and the supporting surface.