Xerophthalmia is characterized by extreme dryness of the conjunctiva and cornea. This is caused due to a failure of the secretory activity of the mucin-secreting goblet cells of the conjunctiva. The conjunctiva and cornea lose their luster and become skin-like in appearance. The condition may even spread to the cornea causing keratoconjunctivitis sicca (Dry Eye) and, if severe, keratomalacia. Xerophthalmia may be due to trauma, exposure, or systemic deficiency of vitamin A.
Vitamin A deficiency is very rare in developed countries.
Dictionary of Optometry and Visual Science, 7th edition.