Biological Effects of Laser Radiation. Volume III. Effects of Carbon Dioxide Laser Radiation on the Rabbit Eye

摘要

Effects of carbon dioxide laser irradiation of the cornea on the anterior segment of the rabbit eye were studied. Corneal temperature elevations were correlated with corneal tissue changes. The average steady state corneal surface temperature at CO2 laser irradiation levels considered to be safe (100 mW/sq. cm.) was 5.5 C, at 200 mW/sq. cm. where irreversible injury occurs, it was less than 10 C, and at 380 mW/sq. cm. it was less than 15 C. At 100 mW/sq cm, there was essentially no elevation in intraocular pressure; at 350 mW/sq cm; elevation was 20 mm Hg. A transient increase in aqueous temperature and pressure occurred on pulsed corneal irradiation. Anterior lenticular indentation, observed on fixation in glutaraldehyde, was determined as due to concomitant anterior chamber temperature and pressure elevation. Indentation was probably due to lens surface temperature in excess of 60 C together with anterior chamber pressure increase. Lens indentation following glutaraldehyde fixation was associated with corneal flattening. Aqueous protein concentration was maximum following irrdiation over the center of the iris. Alterations in lens glutathione, ascorbic acid and soluble lens proteins occurred on suprathreshold irradiation. The glutathione decrement was not due to increased conversion to oxidized glutathione, but was coincidental with alterations in soluble lens protein electrophoretic mobilities. (Author)