the single layer of pigmented cells that abuts the tips of the photoreceptors in the retina. The pigment in the cells reduces light scatter by absorbing photons that elude the photopigments in the photoreceptors. The pigment epithelium is also critical for the health of the photoreceptors because it phagocytoses (engulfs) discarded disks of membrane that are continually shed by the photoreceptors. Also called retinal pigment epithelium (RPE).