a transparent membrane covering the eye that still allows free motion and unobstructed vision
The spectacle refers to the combination of the eye ring and supraloral line.
An ophthalmic device consisting of two ophthalmic lenses and a supporting frame to position and retain the lenses in proper optical alignment with the eyes.
Eye ring and supraloral line together.
is an additional clear covering that overlays the cornea, protecting the eye slit from silt and other abrasive materials. Occurs in bottom dwelling fish and those that live in shallow waters.