Epithelium

Embryologically, the lens epithelium is derived from the cells of the original lens vesicle that did not differentiate into primary lens fibers. The anterior or axial lens epithelium consists of a single layer of cuboidal cells. The basilar surface of the anterior epithelium is oriented toward the anterior lens capsule. The equatorial cells are mitotically active and appear more elongated as they differentiate into lens fibers. Epithelial cells are not typically observed posterior to the lens equator (see Fig 9-2).

Figure 9-1 Posterior aspect of the crystalline lens, depicting its relationship to the peripheral iris and ciliary body. The zonular fibers are translucent and therefore are not visible.

(Courtesy of Hans E. Grossniklaus, MD.)

Figure 9-2 Histologic appearance and structure of the adult lens.

(Courtesy of Tatyana Milman, MD, except for lower right image, courtesy of Nasreen A. Syed, MD.)

Figure 9-3 Lens capsule, periodic acid–Schiff (PAS) stain. Compare the thickness of the anterior capsule (left) with that of the posterior capsule (right). Calibration bar = 0.01 mm.

(Courtesy of Nasreen A. Syed, MD.)

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.