Lens Vesicle

The lens vesicle is a polarized structure, with posterior cells that exit the cell cycle and terminally differentiate into elongated, crystallin-expressing, primary lens fibers that gradually fill the vesicle. In contrast, the anterior cells remain undifferentiated with proliferative capacity. Anterior lens epithelial cells continue to divide throughout life and, as they migrate posteriorly into the equatorial region, they undergo cell cycle exit and differentiate into secondary lens fibers.