cornea is the transparent, dome-shaped, outermost layer that covers the iris and pupil in the front of the eye. Corneal tissue consists of five basic layers: epithelium, Bowman’s layer, stroma, Descemet’s membrane and endothelium. Although the cornea is clear, it contains a highly organized group of cells and proteins. Unlike most tissues in the body, the cornea contains no blood vessels to nourish or protect it against infection. Instead, the cornea receives its nourishment from the tears and aqueous humor fluid that fills the anterior chamber behind it.
The cornea, one of the protective layers of the eye, serves two functions:
Some trauma, including projectile foreign bodies, lacerations and blunt trauma can cause scarring that clouds the cornea. Hereditary conditions including degenerations and dystrophies may also cloud the cornea. The most common hereditary condition seen in young people is keratoconus, a condition in which the cornea assumes a cone shape. Keratoconus usually begins in the teenage years and is most common in people who rub their eyes a lot. These patients may be able to use contact lenses or glasses for a period of time, but unfortunately some may eventually develop corneal scarring and high astigmatism that cannot be corrected without corneal transplantation.
The eye surface can be severely damaged by a number of problems, including:
These problems can result in extensive damage on the eye surface, leading to new blood vessel formation and scarring damage which results in loss of vision.