Abstract
The interdependence of the outer retina and pigment epithelium is illustrated by the functional changes and structural alterations which occur in each in response to choroidal ischaemia, retinal detachment, vitamin A deficiency, and other causes. The pluripotential role of the pigment epithelium is stressed, particularly in relation to the phagocytosis of outer segment material and the ability of this layer to undergo metaplasia into a variety of different cell types. Similarities of all disturbances of the retinal-pigment epithelial interface to retinitis pigmentosa are pointed out, and the significance of the findings in relation to this disease is discussed.