Source : Webster's Revised Unabridged Dictionary (1913)

Blindness \Blind"ness\, n.
   State or condition of being blind, literally or figuratively.
   --Darwin.

   {Color blindness}, inability to distinguish certain color.
      See {Daltonism}.

Source : WordNet®

blindness
     n : lack of sight [syn: {sightlessness}, {cecity}]