This project involves treatment of patients with neovascular proliferation between the retinal pigment epithelium and the sensory retina itself. The project is designed to improve our ability to discriminate between those patients who will be benefited by argon laser therapy and those which will not, and how best the therapy will be applied to such neovascular membranes. Certain other changes involving the choroid are also being studied, including serious detachments of the retinal pigment epithelium, and the relationship coagulation burns placed over these areas will have to the development of further degenerative changes in the human eye. Information so obtained will be subjected to statistical analysis. A suitable group of control patients who are not treated will be matched with those who are treated.