Trans-scleral neodymium: YAG retinal photocoagulation in rabbit eyes

To assess the ability of trans-scleral application of the continuous-wave neodymium: YAG laser to produce retinal ablation with reproducible chorioretinal scars, retinal photocoagulation with the YAG laser was done in four Dutch-belted rabbits (eight eyes). Sharply defined, reproducible lesions were produced that were identical to those found following conventional treatment with the argon laser. At 0.2 J there was destruction of the outer retinal layers with sparing of the inner retinal layers. At 3.0 J full-thickness retinal reorganization was noted; however, even at this energy setting there was minimal histologic evidence of scleral damage. Focused laser energy produced distinctly more retinal destruction and obliteration of the retinal pigment epithelium than unfocused energy. The results suggest that trans-scleral photocoagulation with the YAG laser may be possible and would be particularly applicable in situations in which media opacities preclude visualization of the retina.