Xerophthalmia caused by a severe vitamin A deficiency is described by pathologic dryness of the conjunctiva and cornea.

Other forms of dry eye are associated with aging, poor lid closure, scarring from a previous injury, or autoimmune diseases such as rheumatoid arthritis and Sjögren's syndrome, and these can all cause chronic conjunctivitis.

The World Health Organization classifies xerophthalmia into the following stages:[3] Prophylaxis consists of periodic administration of vitamin A supplements.

Treatment of symptoms usually includes the use of artificial tears in the form of eye drops, increasing the humidity of the environment with humidifiers, and wearing wraparound glasses when outdoors.

Treatment with supplements and/or diet can be successful until the disease progresses as far as corneal ulceration, at which point only an extreme surgery can offer a chance of returning sight.