Experimental subretinal neovascularization in the rabbit.

Subretinal neovascularization (SRN) in the rabbit was induced by subretinal injection of vitreous without rupture of Bruch's membrane. Eight of 26 eyes developed SRN. The incidence of SRN rose from 33% to 57% in a period of 4-40 weeks. Because of the absence of any fluorescein angiographic indication of SRN, these occult new vessels were identified by light and transmission electron microscopy. Histological examination showed that these newly formed vessels are composed of continuous capillaries with the morphologic characteristics of choriocapillaris, including diaphragmed fenestrations, basement membranes, and junctional complexes. The new vessels originated from the choriocapillaris and penetrated through Bruch's membrane into the subretinal space, where they were associated with the degenerated sensory retina and proliferating glial and/or RPE cells. This experiment provides a model of SRN without breaks in Bruch's membrane.