The cornea is the normally clear, front window of the eye that covers the colored iris and round, dark pupil. Light is focused while passing through the cornea, allowing us to see.
A healthy, clear cornea is necessary for good vision. If your cornea is injured or affected by disease, it may become swollen or scarred, and its smoothness and clarity may be lost. Scars, swelling or an irregular shape can cause the cornea to scatter or distort light, resulting in glare or blurry vision.
If a cornea transplant is necessary, the damaged or unhealthy cornea tissue is removed and clear donor cornea tissue is put in its place.
There are many conditions that can affect the clarity of the entire cornea. For instance, trauma or injury to the cornea can cause scarring, as can infections (especially herpes keratitis). A hereditary condition called Fuchs’ dystrophy causes corneal failure. Keratoconus (pictured) causes a steep curving of the cornea. Sometimes corneal failure can occur after an eye surgery such as cataract surgery.
A corneal transplant is needed if vision cannot be corrected satisfactorily with eyeglasses or contact lenses, or if painful swelling cannot be relieved by medications or special contact lenses.