Effect of peripheral cryocoagulation on ocular blood flow.

Using the labeled microsphere impaction technique, we studied the effect of peripheral panretinal transscleral cryocoagulation in pigmented rabbits. One eye of each animal received peripheral cryocoagulation, and the fellow eye of the same animal was used as the control. Thirty-two animals received 40 exposures of peripheral cryocoagulation; twenty-six rabbits received 20 exposures. After 40 exposures of cryocoagulation, choroidal-retinal blood flow was significantly decreased when measured at one to two hours, 24 hours, and two weeks; normal flow recovered by four weeks. After 20 exposures of cryocoagulation, there was a significant reduction in choroidal-retinal blood flow at the earliest measurement time (one to two hours) only. The iris-ciliary body blood flow also was substantially decreased only at the earliest measurement time (one to two hours) and only after 40 exposures.