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 emi tted by this laser. We used an experimental system to create lesions o f various depths in the surface of the rabbit retina in enucleated eye s in vitro to examine the potential application to maneuvers such as r etinotomy and the removal of epiretinal membranes in vitrectomy. With an air/retinal interface, single pulses produced discrete craters in t he 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-t hickness retinotomy, with an adjacent zone of damaged tissue up to 1 m m, caused by effects of volatilization of intervening fluid. The erbiu m:YAG laser may have a role in vitreoretinal surgery.