Early Cryosurgical Chorioretinal Microcirculatory Changes

Abstract

Using circulating dye and an in vivo freezeexcision and dehydration technique in conjunction with ultrathin sections and light microscopy, the dynamic effects of single and multiple transcleral cryoapplication on the choroid and retina were studied. The essential pathogenetic sequence in the choroid is endothelial damage and vascular spasm followed by stasis and thrombosis most marked in the choriocapillaris. The subretinal exudation arising from the choroidal vessels, in association with the fragmentation of the pigment epithelium, is the prime factor in the initiation of the chorioretinal bond. Exudation occurs through an intact Bruch's membrane. With multiple freeze-thaw cycles, the vascular changes in the choroid are potentiated.