The senescent changes in the human retinal pigment epithelium were studied by examining bleached flat mounts prepared from postmortem specimens. The change most characteristic of senescence of the retinal pigment epithelium in general was found to be a progressive pleomorphism involving the size and shape of the cells, nuclei, and pigment granules. In addition, the retinal pigment epithelial cells of the macular area of the aging eye were found to become progressively narrower, higher, and more densely and irregularly pigmented. The retinal pigment epithelial cells of the periphery of the aging eye were found to become progressively broader, lower, vacuolated, and markedly pleomorphic. Drusen which were felt to be the result of decompensation of the vortex venous system of the choroid were found to be associated with significant degenerative changes involving the retinal pigment epithelium of the macular area of the senile eye.
Friedman E, Ts'o MOM. The Retinal Pigment EpitheliumII. Histologic Changes Associated With Age. Arch Ophthalmol. 1968;79(3):315-320. doi:10.1001/archopht.1968.03850040317017