COMPARISON OF TECHNIQUES FOR TRANSSCLERAL DIODE PHOTOCOAGULATION IN THE RABBIT

Purpose: To assess the optimum probe design and treatment parameters f or transscleral diode laser retinopexy. Methods: Transscleral diode ph otocoagulation was performed on the eyes of Dutch-belted rabbits using three different transscleral probes: a straight, 400-mu m diameter pr obe; a prism-tipped 400-mu m diameter probe; and a prism-tipped 900-mu m diameter probe. Results: Transscleral diode photocoagulation with a ll three probe types was an effective method of ablating the retina an d creating chorioretinal adhesions. Both the burn diameter and the mea n radiant output energy requirement increased as the burn duration and probe aperture diameter was increased. Explosive retinal holes were e ncountered in 12% of the burns created with the straight probe. The us e of the prism-tipped probes significantly reduced the incidence of re tinal holes to <4% (P < 0.005). Histopathologically, all burns were gr ade III in intensity with severe choroidal injury. In many of the burn s, there was histopathologic evidence of thermal injury to the inner s clera. The frequency of these inner scleral changes was reduced with a long burn duration (5 seconds) Conclusion: This study confirms that d iode transscleral photocoagulation is a feasible method of thermal ret inopexy. The use of the prism-tipped probes and long duration burns re sulted in the fewest adverse reactions.