Effect of pre-exposure fundus temperature on threshold lesion temperatures in the laser-irradiated rabbit retina

The relationship between pre-exposure fundus temperature and the temperature rise which produces a threshold burn was examined in rabbit eyes exposed to an Argon c. w. laser (4,880 A) for 10 seconds. The posterior pole of the eye was surgically exposed and a 20-micron tip diameter probe was inserted into the ocular fundus to measure temperature rises. The temperature rise for threshold burns linearly increased as preexposure fundus temperature decreased, implying a constant threshold temperature. Threshold temperature was indirectly predicted to be 52.4 degrees C. using a system with an estimated error of plus or minus 1/2 degrees C.