Development and ultrastructure of peripheral subretinal neovascularizations.

Anterior to the equator an additional vascular layer can regularly be found between peripheral retina and choroid. The vessels are located within Bruch's membrane, subjacent to the retinal pigment epithelium. Apparently, this layer is not present at birth and develops at a relatively young age. With the electron microscope all steps of vasculogenesis could be followed. The presence of such vessels also in the eye of a 29-year-old individual suggests that they represent a physiologic condition rather than an ageing change. In contrast to the subretinal neovascular membranes of the posterior fundus, these peripheral neovascularizations show no relation to any known fundus disease.