ABSTRACT
ANATOMY AND PHYSIOLOGY The cornea and sclera comprise the fibrous tunic of the globe. The transitional zone where the sclera superficially overlaps the cornea is termed the limbus. This overlap is widest dorsal and ventrally. When the globe is viewed rostrally the cornea is slightly horizontally elongated, especially in ungulates, and when viewed from the side the cornea has a greater curvature than the sclera (10.1, 10.2). The cornea of the dog has an average radius of curvature of 8.5 mm and varies from 13-17 mm in the horizontal axis and 12-16 mm in the vertical axis1, 2. The cat cornea has an average radius of curvature of 8.6 mm, horizontal axis of 17 mm, and vertical axis of 16 mm3. Corneal measurements vary significantly in the horse, with the horizontal axis ranging from 28-34 mm and vertical axis ranging from 23-27 mm1, 4.
