ERBIUM-YAG LASER PHOTOTHERMAL RETINAL ABLATION IN ENUCLEATED RABBIT EYES

The erbium:YAG laser has been shown to produce precise tissue ablation because of the high water absorption of the 2.94-mu m wave-length emitted by this laser. We used an experimental system to create lesions of various depths in the surface of the rabbit retina in enucleated eyes in vitro to examine the potential application to maneuvers such as retinotomy and the removal of epiretinal membranes in vitrectomy. With an air/retinal interface, single pulses produced discrete craters in the retinal surface with a depth proportional to fluence, ranging from 30 mu m for a pulse of 1.3 J/cm(2) to a full-thickness retinotomy at 3.9 J/cm(2). An adjacent zone of coagulated tissue ranging in size from 15 to 40 mu m was noted. Multiple pulses had an additive effect. With a fluid/retinal interface, 20 pulses of 3.6 J/cm(2) produced a full-thickness retinotomy, with an adjacent zone of damaged tissue up to 1 mm, caused by effects of volatilization of intervening fluid. The erbium:YAG laser may have a role in vitreoretinal surgery.