The retinal pigment epithelium is a critical tissue within the eye it lies directly behind the retina where it provides metabolic support to the photoreceptors and controls their local. The retinal pigment epithelium is a critical tissue within the eye it lies directly behind the retina where it provides metabolic support to the photoreceptors and controls their local environment as a result the rpe is vital to retinal function but also a site of aging and disease that cause dysfunction and visual loss. An abstract is unavailable this article is available as a pdf only. The retinal pigment epithelium book read reviews from worlds largest community for readers the retinal pigment epithelium is a critical tissue within