Corneal abrasion is defined as?

• A. An alteration in the epithelial layer of the cornea due to trauma, foreign bodies, or chemical exposure
• B. Inflammation of the optic nerve
• C. Degeneration of the retina
• D. Clouding of the lens

Answer: (A)

Corneal abrasion is a disruption of the corneal surface epithelium caused by trauma, a foreign body, or chemical exposure. The epithelium is the outer protective layer of the cornea, so when it’s damaged, the eye hurts, tears, and often feels like there’s something in the eye. On examination with fluorescein dye, you’ll see a bright green defect where the epithelial layer is broken, which helps confirm the surface nature of the injury. This definition distinguishes it from conditions that involve other parts of the eye: inflammation of the optic nerve affects vision through the optic pathway; degeneration of the retina involves the back layer of light-detecting cells; and clouding of the lens refers to a cataract causing lens opacity.