INFLUENCE OF EXPOSURE TIME ON INFLAMMATORY RESPONSE TO NEODYMIUM - YAG CYCLOPHOTOCOAGULATION IN RABBITS

Objective: To evaluate the influence of duration of exposure on the inflammatory response to transscleral neodymium:YAG cyclophotocoagulation. Methods: Transscleral cyclophotocoagulation was performed with a contact, Nd:YAG, continuous-wave laser on one eye of 48 Dutch belted rabbits, 10 W and 0.2 second used in half and 1 W and 2 seconds in the other half. One third of each group was evaluated on the operative day and the other thirds on postoperative days 3 and 10. Tissue reaction was inspected grossly and by light microscopy, and inflammatory responses were measured by aqueous leukocyte and erythrocyte counts, aqueous and vitreous protein levels, aqueous prostaglandin levels, and iris and ciliary body myeloperoxidase activity. Results: The shorter-duration protocol was associated with more ciliary epithelial disruption and significantly greater inflammatory responses by one or more of the measures at all times. Conclusion: When energy is constant, a shorter duration of exposure with transscleral Nd:YAG cyclophotocoagulation in rabbits is associated with greater tissue disruption and inflammation.