Abundant melanocytes, as well as occasional macrophages, lymphocytes, mast cells, and plasma cells, appear throughout the choroidal stroma. The intercellular space contains collagen fibers and nerve fibers. In lightly pigmented eyes, pigmentation in the choroid is sparse compared with that of darkly pigmented eyes.
Figure 2-26 Lobular pattern of the choriocapillaris. A, Note that the RPE is internal to the choriocapillaris. B, Electron micrograph of the choriocapillaris and larger choroidal vessels. A = arteries; C = choriocapillaris; CA = choroidal arteriole; CV = choroidal venule; V = veins.
(Part A reproduced with permission from Hayreh SS. The choriocapillaris. Albrecht Von Graefes Arch Klin Exp Ophthalmol. 1974;192(3):165–179. Part B courtesy of A. Fryczkowski, MD.)
Figure 2-27 Electron micrograph of the choriocapillaris. Fenestrations of the vessel walls are depicted. En = endothelial cell; Fe = fenestrations; Lu = lumen.
(Adapted with permission from Spalton D, Hitchings R, Hunter P. Atlas of Clinical Ophthalmology. 3rd ed. Oxford: Elsevier/Mosby; 2005:261.)
Excerpted from BCSC 2020-2021 series: Section 2 - Fundamentals and Principles of Ophthalmology. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.