Threshold Lesion Temperatures in Argon Laser-Irradiated Rabbit Eyes

The purpose of this research was to measure threshold temperatures corresponding to the formation of minimum ophthalmoscopically visible lesions induced in rabbit ocular fundi by a 10-s exposure from an argon c. w. laser (4880 Å). The backside of the eye was surgically exposed and a specially designed microthermocouple with a 20-micron dia tip was inserted into the pigment epithelium to measure temperature rises. The mean threshold temperature for 30 measurements in 13 rabbits was 54° C and the standard deviation was 3° C. System error was estimated at 5 percent of temperature rise, or slightly less than ±1/2° C.