The lens is thinnest at the posterior pole. The crystalline lens is surrounded by a lens capsule. Lens capsule is a thin transparent elastic membrane secreted by the lens epithelial cells largely composed of type IV collagen. The capsule is 11- 15microm thick at the anterior pole. The posterior capsule thickness decreases to a minimum at the posterior pole to about 4microm. Ref: Adler's Physiology of the Eye: Expe Consult by Leonard A Levin, Page 47