Laser Coagulation of the Anterior Segment

Abstract

The irides of ten pigmented Dutch rabbits were coagulated with the pulsed ruby laser (0.3 joules). Single firings produced atrophic hyperpigmented lesions. The hyperpigmentation was due to pigment filled macrophages. In another group of young pigmented Dutch rabbits, laser coagulations were done on each eye in two peripheral iris sites. This was repeated three more times at weekly intervals. In 42 of 44 sites peripheral colobomas developed. Lens damage was not seen over a nine month observation period. During the stage of partial focal iris atrophy, laser light filtered through the iris and the retina was accidentally coagulated. In a third group, a lower energy level (0.15 joules) did not harm the retina, but the incidence of iridotomies fell to 20%. Though the present technique with the higher energy yields a high percentage of peripheral iridotomy lesions, the retinal damage precludes its use as a method for refashioning pupils or as a substitute for peripheral iridectomy.