Vitamin A deficiency is a result of prolonged consumption of food with insufficient beta-carotene and vitamin A. In the western world it most often happens in people with diseases affecting the ability of intestines to absorb fat, as well as in alcoholics. The diseases that may contribute to vitamin A deficiency are celiac disease, cholestasis and cystic fibrosis. Vitamin A deficiency is widespread in Southeast Asia where the one of the most important parts of diet is lacking in vitamin A polished rice.

The earliest symptom of vitamin A deficiency is night blindness whereas more prolonged vitamin A deficiency usually results in drying of the conjunctiva. If not treated this may finally result in the cornea. If the vitamin A deficiency still c continues cornea will shrivel up and become ulcerated. In the end infection and inflammation occur in the interior of the eye which leads to total and irreversible blindness.