Source : Webster's Revised Unabridged Dictionary (1913)

Retinal \Ret"i*nal\, a. (Anat.)
   Of or pertaining to the retina.

   {Retinal purple} (Physiol. Chem.), the visual purple.

Source : WordNet®

retinal
     adj : in or relating to the retina of the eye; "retinal cells"

retinal
     n : either of two yellow to red retinal pigments formed from
         Rhodopsin by the action of light [syn: {retinene}]