Peroxidase permeability of the cryogenic chorioretinal adhesion.

Under normal conditions the retinal pigment epithelium does not permit passage of peroxidase tracers. Photocoagulation disrupts this barrier. Rhesus monkeys which received transconjunctival cryotheropy showed a similar disruption, with leakage of horseradish peroxidase into the retina. This leakage persisted for the 6-month duration of the experiment. One month after treatment, a firm chorioretinal adhesion was present, characterized by gliosis, adherent junctions, and cellular interdigitation. The anatomic features of the cryogenic chorioretinal adhesion were similar to those previously described in human eyes.