Tunica Vasculosa Lentis
Around 1 month of gestation, the hyaloid artery, which enters the eye at the optic nerve head (also called the optic disc), branches to form a network of capillaries, the tunica vasculosa lentis, on the posterior surface of the lens capsule (Fig 4-3). These capillaries grow toward the equator of the lens, where they anastomose with a second network of capillaries, called the anterior pupillary membrane, which derives from the ciliary veins and covers the anterior surface of the lens. At approximately 9 weeks of gestation, the capillary network surrounding the lens is fully developed; it disappears by an orderly process of programmed cell death shortly before birth. Sometimes a remnant of the tunica vasculosa lentis persists as a small opacity or strand, called a Mittendorf dot (discussed later in this chapter), on the posterior aspect of the lens. In other eyes, remnants of the pupillary membrane are often visible as pupillary strands.
Excerpted from BCSC 2020-2021 series: Section 11 - Lens and Cataract. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.