Evaluation of cellular adhesions on silicone and poly(methyl methacrylate) intraocular lenses in monkey eyes: An electron microscopic study

Purpose: To assess the biocompatibility of intraocular lens (IOL) material by studying the number of cells adhering to IOLs in monkey eyes. Setting: Department of Ophthalmology, Kyushu University, Fukuoka, Japan. Methods: Silicone or poly(methyl methacrylate) (PMMA) IOL implantation was performed in 21 monkeys. One eye of each animal had surgery. The IOL-implanted eyes were enucleated 1, 2, 3, 5, and 7 days and 1, 3, 4, 5, and 9 months after the procedure. One eye was studied at each time. Cells on the anterior IOL surface were photographed using a scanning electron microscope, counted and assessed with NEC, Graphtec, and Nikon equipment, and then observed using a transmission electron microscope. Results: Leukocytes, macrophages, and giant cells were found on the anterior IOL surface. Numerous cells were observed on the PMMA IOLs in the early postoperative period; they gradually decreased. Few cells were seen on the silicone IOLs during the course of the study. The giant cells became larger during the postoperative period. Conclusion: The foreign-body reaction to silicone IOLs in monkey eyes was less than that to PMMA IOLs.