It can also get contaminated with tissue fragments, particularly in some disorders. Blood and debris can be washed from the vitreous as the fluid is refreshed, or surgical replacement can be performed in serious cases. Congenital abnormalities can affect the structure of the eyes. If the structure of the eye is affected, the drainage systems for the aqueous and vitreous can get plugged resulting in glaucoma. Glaucoma is the build up of fluid in the eye that results either from a blockage of the drainage system, or from eyes that produce fluid faster than they filter-off old fluid.
Structural damage can also affect the operation of the pupil or the lens.
Colobomas are birth defects. The developing eye zips shut along the vertical axis in utero. If it fails to zip shut, a slit results. The slit zips shut from the back toward the front of the eye. Many of these refractive errors are significantly large.