Secondary Lens Fibers
After they proliferate, the epithelial cells near the lens equator elongate to form secondary lens fibers. The anterior aspect of each developing lens fiber extends anteriorly beneath the lens epithelium, toward the anterior pole of the lens. The posterior aspect of each developing lens fiber extends posteriorly along the capsule, toward the posterior pole of the lens. In this manner, new lens fibers are continually formed, layer upon layer. As each secondary fiber cell detaches from the capsule, it loses its nucleus and membrane-bound organelles. The secondary lens fibers formed between 2 and 8 months of gestation make up the fetal nucleus.
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.