Noncontact transscleral neodymium-YAG laser photocoagulation of the pigmented rabbit retina.

We studied the applicability of transscleral delivery of noncontact neodymium-YAG laser in its free-running mode (10 milliseconds) in creating chorioretinal lesions in 16 rabbits. After the laser was applied, the eyes were studied by indirect ophthalmoscopy, light microscopy, and electron microscopy. Lesions generated with low-energy and defocus settings were characterized by intact sclera, variable clumping of the pigmented choroidal lamellae, destruction of choriocapillaris, and loss of the retinal pigment epithelium. In the central region of laser exposure, vacuolization of the retinal pigment epithelium and outer retina were observed. No scleral changes were noted. In contrast with lesions produced with high-energy and/or high-defocus settings, these lesions were produced without hemorrhagic phenomena or breaks in the neurosensory retina. These data demonstrate that noncontact transscleral neodymium-YAG photocoagulation is capable of very localized, selective destruction of the retina and choroid and deserves further study.