The cornea is a transparent covering of the front of the eye. It covers the interior contents of the eye such as the iris (the colored part of the eye). Just look in the mirror and clear region surrounded by the white part of the eye is the cornea.

The very front part of the cornea is the epithelium, the surface layer of cells covering this transparent layer. When something scratches the eye or if contact lenses or not handled properly, the epithelium can be torn off. This results in a painful corneal abrasion. This condition is easily detected by your ophthalmologist. Urgent treatment is needed to prevent the affected area from becoming infected and developing into a corneal ulcer.

See Corneal Ulcer