Experimental intravitreal proliferation and neovascularization in the cynomolgus monkey

An experimental model for intravitreal cellular proliferation was produced by injection of carbon microparticles into the vitreous of nine cynomolgus monkeys. Eighteen eyes were studied following enucleations 10 weeks after the injections. Histological examinations showed retinal folds or detachments in 16 eyes, while 6 of those had total detachments. Eight eyes contained transvitreal fibrovascular strands, passing from the optic disk to a "cyclitic" retrolental membrane. The strands and membranes were composed mainly of infiltrates of macrophages, inflammatory cells, fibroblasts, newly formed vessels and van Gieson-staining collagen. Epiretinal proliferation of glial cells also occurred. These experiments indicate that a primarily phagocytic cellular invasion into the vitreous is capable of stimulating further cellular migration and growth and for inducing fibrovascular proliferations.