[Biological effect of laser-photo-coagulation on the retina (author's transl)].

The effects of laser-photo-coagulation on retina, pigment epithelium and choroid has been studied in animals (rabbit and mini-pig). During the first two hours after photocoagulation the permeability of the blood-retinal barrier and of the pigment epithelium is temporarily increased. Later on (2-4 days) pigment epithelial cells proliferate within the coagulated areas and "tighten" the epithelial leaks. Photoreceptor outer segments undergo during the same period reversible breakdown. Normal retinal blood vessels are hardly altered by photocoagulation whereas pathological or neoformed vessels may be obliterated. Functional deficiences are observed after extensive photocoagulations only and even then rarely implicated by the patients.