The basal portion of the RPE is attached to Bruch membrane, which has 5 layers. Starting with the innermost, these layers (see Fig 1-9) are the
basement membrane of the RPE
inner collagenous zone
middle layer of elastic fibers
outer collagenous zone
basement membrane of the endothelium of the choriocapillaris
Degeneration of Bruch membrane over time is associated with buildup of lipids and oxidatively damaged materials as well as calcification. In some disease states, such as pseudoxanthoma elasticum, extensive Bruch membrane calcification leads to fractures, for example, angioid streaks. In age-related macular degeneration, areas of calcification with microscopic breaks have also been found.
Excerpted from BCSC 2020-2021 series: Section 10 - Glaucoma. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.