Sensitivity of the Rhesus Monkey Cornea and Surrounding Tissues to Heat Produced by CO2 Laser Radiation
LETTERMAN ARMY INST OF RESEARCH PRESIDIO OF SAN FRANCISCO CA
Pagination or Media Count:
Rhesus monkeys were trained to report the presence of heat produced by a CO2 laser system. Four, 8, and 16 mm diameter beams were directed at the cornea, lids, and face of the animals at irradiances ranging from 1 to 200 mwsq cm, and the results compared to those of other investigators who utilized human subjects. Several conclusions can be made based upon this study. 1 The cornea does not appear to be sensitive to heat produced by a CO2 laser system at irradiances twice the recommended safety level. 2 No changes were observed in the corneas, lids, or facial tissues of the animals after several thousand 20- second exposures at these irradiances. 3 The threshold for sensitivity to CO2 laser radiation with the 8 mm diameter beam was between 25 and 50 mwsq cm, while for the 16 mm beam condition it was between 4 and 20 mwsq cm. 4 No differences in the rhesus monkey responses were observed between the 8 mm beam directed at the cornea and lids and the same beam directed to a non-hairy area of the face, while responses to the 4 mm diameter beam were different when skin exposures were compared to corneal exposures.