The Collaborative International Dictionary of English v.0.48:

Retina \Ret"i*na\, n. [NL., from L. rete a net. Cf. Reticule.]
   (Anat.)
   The delicate membrane by which the back part of the globe of
   the eye is lined, and in which the fibers of the optic nerve
   terminate. See Eye.
   [1913 Webster]

   Note: The fibers of the optic nerve and the retinal blood
         vessels spread out upon the front surface of the
         retina, while the sensory layer (called Jacob's
         membrane), containing the rods and cones, is on the
         back side, next the choroid coat.
         [1913 Webster]

WordNet (r) 3.0 (2006):

retina
    n 1: the innermost light-sensitive membrane covering the back
         wall of the eyeball; it is continuous with the optic nerve

Moby Thesaurus II by Grady Ward, 1.0:

27 Moby Thesaurus words for "retina":
   baby blues, banjo eyes, bright eyes, clear eyes, cornea, eye,
   eyeball, eyelid, goggle eyes, iris, lens, lid, naked eye,
   nictitating membrane, oculus, optic, optic nerve, orb,
   organ of vision, peeper, popeyes, pupil, saucer eyes, sclera,
   starry orbs, unaided eye, visual organ