abnormal retinal pigment epithelium morphology retinal pigment epithelium atrophy acquired diminution of the size of the epithelial layer of the retina composed of cells containing pigment granules, associated with wasting as from death and reabsorbtion of cells, diminished cellular proliferation, decreased cellular volume, pressure, ischemia, malnutrition, reduced function or malfunction, or hormonal changes atrophy of retinal pigment epithelium MPheno.ontology MP:0005548