Animals

Infant rhesus monkeys (Macaca mulatta, n=11) undergoing lens-treatment for a refractive study were used for this experiment. Monkeys were obtained at 2 weeks of age and housed in a vivarium illuminated with broadband white fluorescent lighting (approximately 1000 lux) on a 12hr-light/12hr-dark cycle with lights on beginning at 7:00 am. For enrichment purposes and to increase the complexity of the visual experience, beginning at 4 weeks of age animals were given 1.5 hours of group playtime each day. Monkey-human interaction was encouraged, and both experimenters and husbandry staff devoted time to foster positive relationships with each animal using petting, treats, singing/vocalizing, carrying animals around the nursery, and playing in the playroom. Animal husbandry protocols were in accordance with the Guide for the Care and Use of Laboratory Animals. Experimental protocols were approved by the University of Houston Institutional Animal Care and Use Committee and were in accordance with the ARVO Statement for the Use of Animals in Ophthalmic and Vision Research.