Atropine inhibition of echothiophate cataractogenesis in monkeys.

One cynomolgus and three vervet monkeys were treated topicall twice daily in one eye with 63 microgram of echothiophate iodide and 750 microgram of atropine sulfate. The opposite eyes were treated with echothiophate alone. The eyes treated with echothiophate alone all developed posterior and/or anterior subcapsular cataracts within 26 to 66 days. The echothiophate plus atropine-treated cynomolgus eye developed a cataracts of much delayed onset and lesser severity compared to its echothiophate-only-treated fellow. None of the echothiophate plus atropine-treated vervet eyes developed cataracts during the 121 (two eyes) or 231 (one eye) days of treatment. After 121 days of echothiophate plus atropine treatment, two vervet eyes were switched to echothiophate alone. Both eyes developed unequivocal posterior and anterior subcapsular lens opacities, one within 51 and one within 71 days after the switch. We conclude that atropine inhibits echothiophate cataracto-genesis in vervet and cynomolgus monkeys.