The Collaborative International Dictionary of English v.0.48:

Glaucoma \Glau*co"ma\, n. [L., fr. Gr. glay`kwma, fr. glayko`s
   light gray, blue gray.] (Med.)
   Dimness or abolition of sight, with a diminution of
   transparency, a bluish or greenish tinge of the refracting
   media of the eye, and a hard inelastic condition of the
   eyeball, with marked increase of tension within the eyeball.
   [1913 Webster]

WordNet (r) 3.0 (2006):

glaucoma
    n 1: an eye disease that damages the optic nerve and impairs
         vision (sometimes progressing to blindness); "contrary to
         popular belief, glaucoma is not always caused by elevated
         intraocular pressure"

Moby Thesaurus II by Grady Ward, 1.0:

53 Moby Thesaurus words for "glaucoma":
   ablepsia, amaurosis, benightedness, blepharitis, blind side,
   blind spot, blindfolding, blinding, blindness, blurring the eyes,
   cataract, cecity, choroiditis, conjunctivitis, cross-eye, darkness,
   defective vision, depriving of sight, detached retina,
   dim-sightedness, drop serene, economic blindness, esotropia,
   ever-during dark, excecation, eye defect, eyelessness,
   gutta serena, hoodwinking, iritis, keratitis, lack of vision,
   making blind, niphablepsia, optic neuritis, partial blindness,
   pink eye, psychic blindness, reduced sight, retinoblastoma,
   sightless eyes, sightlessness, snow blindness, soul-blindness,
   spiritual blindness, stone-blindness, sty, total blindness,
   trachoma, unenlightenment, unseeingness, uveitis, walleye