orthoscope

noun Ophthalmology.

1. (formerly) an instrument for examining the internal structures of the eye through a layer of water that neutralizes the refraction of the cornea.

noun

1. med obsolete a 19th-century instrument for viewing the fundus of the eye through a layer of water, which eliminates distortion caused by the cornea

n.

1. An instrument used to examine the eye that eliminates corneal refraction by means of a layer of water.