Source : Webster's Revised Unabridged Dictionary (1913)

Orthoscope \Or"tho*scope\, n. [Ortho- + -scope.] (Physyol.)
   An instrument designed to show the condition of the
   superficial portions of the eye.

Source : WordNet®

orthoscope
     n : an ophthalmoscope with a layer of water to neutralize the
         refraction of the cornea