Anterior Lenticonus and Lentiglobus
The anterior surface of the lens can assume an abnormal shape, either conical (lenticonus) or spherical (lentiglobus). Clinically, these abnormalities can be seen in the red reflex, where, by retroillumination, they appear as an “oil droplet.” Anterior lenticonus may be unilateral or bilateral.
Histologic examination reveals thinning of and small defects in the anterior lens capsule, a decrease in the number of anterior lens epithelial cells, and bulging of the anterior cortex. Electron microscopy demonstrates alterations in lens capsule collagen, and immunohistochemical analysis reveals abnormalities in type IV collagen.
Bilateral anterior lenticonus is usually associated with Alport syndrome, which is most often an X-linked disorder characterized by hemorrhagic nephritis, deafness, anterior polar cataract, and retinal flecks. Mutations in type IV collagen genes—specifically, COL4A3, COL4A4, and COL4A5—have been described in some forms of Alport syndrome.
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.