Description and Symptoms
A Corneal Abrasion is a scratch on the surface of the eye. The transparent window at the front of the eye is the cornea. It consists of several layers. The outermost layer is the epithelium. This layer protects the cornea from bacteria and is the first point at which light is focused in the eye. The corneal nerves lie just beneath the epithelium, and these are sensitive nerve endings.
It is possible that the surface epithelial layer is disturbed as in a corneal scratch or abrasion. Then the exposed nerve endings make you feel like there is glass or grit in the eye and it is painful.