Choroidal microvascular repair after argon laser photocoagulation.

We studied the repair process of the choriocapillaris after argon laser retinal photocoagulation in the domestic cat with a plastic injection-corrosion technique and scanning electron microscopy. Retinal scatter photocoagulation was applied to the tapetum at threshold-, moderate-, and high-intensity levels and specimens prepared one, ten, and 30 days later. At 24 hours after photocoagulation, obstruction of the choriocapillaris was always present regardless of the power used. In lesions produced by higher-intensity energy levels, choriocapillaris defects had larger diameters and larger vessels were affected more severely. At ten days, there were early signs of choriocapillaris repair. At 30 days, choriocapillaris occupied almost the entire area of the defect, although the normal lobular architecture was not present.