1. Abnormal and severe dryness of the surface of the cornea and conjunctiva (mucous membrane that lines the inner surface of the eyelid and the exposed surface of the eyeball), which may occur in pemphigus (acute or chronic skin diseases characterized by groups of itching blisters), vitamin A deficiency, or certain autoimmune syndromes.
2. A dry and thickened condition of the conjunctiva, sometimes following chronic conjunctivitis, disease of the lacrimal apparatus, or vitamin-A deficiency.