Have you ever fallen down and scraped your knee or elbow? I was an active kid who spent most days after school climbing trees and riding my bicycle around the neighborhood, and came home with abrasions on my knees many many times. Remember how painful they were?
Imagine the skin of the eye getting an abrasion like your knee. This can happen from relatively trivial trauma, like a scratch from your fingernail or being brushed by a tree branch. The cornea is the surface layer of the eye and it has a skin layer similar to the skin on our bodies, but has 5 times the number of pain receptors per square mm compared to the skin on your body. For that reason, cornea abrasions are exquisitely painful.
Fortunately, the abraded cells grow over very quickly with appropriate treatment, and the patient feels relief of the pain within days. However, the problem doesn’t always end there.
Unlike the skin on your body, which heals completely relatively quickly, the skin on your cornea takes a long time to heal completely. New cells grow over to cover the abrasion in a matter of days, but these cells are immature and don’t stick well to each other. It takes a period of months to years for these cells to mature and stick firmly to each other. In the meantime, patients are at risk for recurrent cornea erosions.
When the cells are immature, minor trauma can cause the sheet of cells to detach from the cornea, and the patient sustains a cornea abrasion all over again. Sometimes the trauma is nothing more than the patient opening his eyes in the morning- the movement of the eyelid over the immature sheet of cornea cells is enough to cause the abrasion to happen!
Although it is a painful and troublesome condition, recurrent cornea erosions can be treated. Patients will require plenty of eyedrops and ointments to lubricate the eye, especially at night, and usually for many months to years. If the condition recurs over and over again, additional treatment such as specially fitted contact lenses or laser treatment can be considered.