What does the term "corneal abrasion" describe?

The term "corneal abrasion" specifically refers to a scratch or damage to the outer layer of the cornea, known as the epithelium. This condition can occur due to various causes such as foreign objects, contact lens usage, or trauma. The cornea is essential for vision and serves as the eye's protective shield, and an abrasion can lead to symptoms like pain, redness, and sensitivity to light. Understanding this definition is critical for recognizing the potential complications that may arise from such injuries, as they can lead to infection or vision issues if not properly treated.

The other options do not accurately define a corneal abrasion; they refer to different concepts that involve the cornea, such as diseases or surgical procedures, but they do not describe the specific nature of a scratch on the cornea.