The clear portion of the eye is the cornea and it is made of layers of cells arranged in a unique fashion so as to be transparent. The white area called the sclera is made of tough fibers rich in blood vessels which transport oxygen and nutrients to the eye. The eyeball itself is formed by layers of tissue (see Figures 1 & 2). The eye is protected by being sealed in a bony eye socket supported by lubricating tissues, muscles, and eyelids. The eyeball functions to gather light and transmit it into electrical impulses which are interpreted by the brain to form images. The visual system is an important sense available to the canine.
