[Dye laser photocoagulation treatment for experimental subretinal neovascularization. 2. Histopathological findings of unsuccess lesions].

We observed the histopathological process in unhealed lesions following photocoagulation treatment for experimental subretinal neovascularization (SRN) in rhesus monkey eyes. Long-lasting SRNs were produced experimentally by the method which we previously reported. These SRNs were treated by a 590nm dye laser beam, and were examined clinically and histopathologically. Lesions in which insufficient photocoagulation treatment was performed showed serous fluid accumulation and fluorescein angiography revealed remaining neovascularization. In these lesions abundant patent neovascularization was seen with proliferation of spindle-shaped fibroblast-like retinal pigment epithelial (RPE) cells in the subretinal space. These metaplastic RPE cells produced matrix and abundant collagen fiber around the cells. The above results showed that insufficient photocoagulation induced neovascularization and proliferation of RPE cells in the subretinal space and promoted the formation of fibrovascular membrane.