Peroxidase diffusion in the normal and photocoagulated retina.

To study diffusion pathioays in normal and photocoagulated mammalian retina, xenon photocoagulation was applied to one eye in each of a group of rabbits; three iveeks later, peroxidase was injected in both eyes; thereafter, the animals were killed at intervals and the tissues were studied with electron microscopy. In the normal eyes, peroxidase diffused rapidly through the intercellular spaces in all layers of the sensory retina, but diffusion stopped abruptly at the zonulae occludentes in the intercellular spaces of the pigment epithelium. Three weeks after photocoagulalion, peroxidase diffused rapidly through all layers of the scar to come in contact with Bruch's membrane. Consideration has been given to the anatomical basis for these observations, and to the mechanism of the action of photocoagulation in certain retinal diseases.