The Collaborative International Dictionary of English v.0.48:

Xerophthalmia \Xe`roph*thal"mi*a\, n. [L., fr. Gr. ?; xhro`s dry
   + ? the eye. See Ophthalmia.] (Med.)
   An abnormal dryness of the eyeball produced usually by
   long-continued inflammation and subsequent atrophy of the
   conjunctiva.
   [1913 Webster]

WordNet (r) 3.0 (2006):

xerophthalmia
    n 1: abnormal dryness of the conjunctiva and cornea of the eyes;
         may be due to a systemic deficiency of vitamin A [syn:
         xerophthalmia, xerophthalmus, xeroma, conjunctivitis
         arida]