A progressive disease of the eye caused by extreme vitamin A deficiency, in which the cornea (the transparent front part of the eyeball) becomes ulcerated and opaque. Perforation of the cornea is also widespread, usually leading to loss of the eye via infection. The disorder generally arises is extremely malnourished children and is a commonly seen cause of blindness in third world countries.
In the early stages, the damage can be undone by treatment with heavy doses of vitamin A but, if the condition is left untreated, blindness is generally unavoidable.
A general term used to describe a range of disorders of the cornea (the transparent part of the eyeball).
Actinic keratopathy is a painful condition in which the outer layer of the cornea is impaired by ultraviolet light given off from the un, reflected from surfaces such as snow (in which case the problem is called snow-blindness), or given off by artificial sources such as ac-welding torches or sunbeds.
Exposure keratopathy is corneal damage due to lack of the protection afforded by the tear film and blink reflex. It can arise in conditions in which the eyelids insufficiently cover the cornea, including extreme facial palsy, ectropion, and exophthalmos.