Retinal Pigment Epithelium
The RPE consists of a monolayer of hexagonal cells with apical microvilli. RPE cells appear cuboidal in cross section. The cytoplasm of RPE cells contains numerous melanosomes and lipofuscin. The RPE basement membrane forms the inner layer of Bruch membrane. In contrast to the retina, the RPE exhibits more subtle topographic variations. In the macula, the RPE is taller, narrower, and more heavily pigmented than in other regions, and it forms a regular hexagonal array. Anterior to the macula, RPE cells are shorter and larger in diameter. Variability in the diameter of RPE cells increases in the peripheral retina. The amount of cytoplasmic lipofuscin increases with age, particularly in the macula.
Excerpted from BCSC 2020-2021 series: Section 4 - Ophthalmic Pathology and Intraocular Tumors. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.