Lamina Cribrosa is a thin, sieve-like portion of sclera at the base of the optic disc through which retinal nerve fibers leave the eye to form the optic nerve.
It is formed by a multilayered network of collagen fibers that insert into the scleral canal wall. The lamina cribrosa is thought to help maintain the pressure gradient between the inside of the eye and the surrounding tissue.
As a result in intraocular pressure it bulges slightly outwards. Being structurally weaker than the much thicker and denser sclera, the lamina cribrosa is more sensitive to changes in the intraocular pressure and tends to react to increased
pressure through posterior displacement. This is thought to be one of the causes of nerve damage in glaucoma, as the displacement of the lamina cribrosa causes the pores to deform and pinch the traversing nerve fibers and blood vessels.