ABSTRACT
The eye is a remarkable organ that provides the sense of sight. Vision is responsible for 75% of the information we receive about our world, and nearly half of the brain is devoted to either direct or indirect processing of visual information. Given the importance of visual input, the eye's structure is appropriately complex. The eye is often compared to a camera. The front half of the eye is dedicated to the gathering and transmission of light, while the rear half is dedicated to absorbing and processing the light as stimuli. Surrounding the eye are supporting structures that protect the eye and assist in vision called the adnexa. These include the eyelids, tear glands and surrounding area. The eyelids enclose the orbit, protect the globe and help distribute tears across the anterior surfaces. Tears are made up of three layers; the outer layer is the oily layer, the middle is the aqueous, and the base layer is the mucus layer.
