Safety of Intracameral Injection of Minimal Bactericidal Concentration of Povidone Iodine on the Corneal Endothelium in a Rabbit Model

PURPOSE:To investigate the safety of intracameral injection of minimum bactericidal concentration (MBC) of povidone iodine (PI) on the corneal endothelium in a rabbit model as a proposed method of prophylaxis against postoperative endophthalmitis. METHODS:We included 32 New Zealand white rabbits in the study. Twenty-four rabbits received intracameral injections of 0.1 mL of 0.25% PI, and they were sequentially killed at intervals; first, seventh, and 14th day. The control group included 4 rabbits that received intracameral injections of 0.1 mL normal saline, and 4 rabbits that underwent the same intraocular procedure without injections (sham operated). Slit-lamp examination and ultrasonic corneal pachymetry were performed before and after injections for both eyes. The corneas were histopathologically examined by light and electron microscopy. RESULTS:MBC of PI (0.25%) was toxic to rabbitsʼ corneal endothelium as evident by histopathological changes, corneal edema, and increased corneal thickness on day 1. Signs of healing were obvious on day 7 and were almost complete on day 14, as detected by histopathology, subsidence of corneal edema, and normalization of corneal thickness. CONCLUSIONS:MBC (0.25%) of PI was found toxic to the rabbitsʼ corneal endothelium, with progressive regeneration and complete healing within 2 weeks. To our knowledge, we are the first to use MBC of PI in intracameral injection trials. Further studies on primates, which have more comparable regenerative capacity to humansʼ corneal endothelium, are encouraged to evaluate their endothelial healing response.