Corneal abrasions are generally a result of trauma to the surface of the eye. Common causes include jabbing a finger into an eye, walking into a tree branch, getting grit in the eye and then rubbing the eye or being hit with a piece of projectile metal.
A foreign body in the eye may also cause a scratch if the eye is rubbed. Symptoms of corneal abrasion could possibly include pain, increased sensitivity to light, feeling that there is a foreign body in the eye, swollen eyelids, and blurred vision. You should call your eye doctor if you experience any of these symptoms.
Superficial corneal injuries normally heal very rapidly with treatment, and the eye should be back to normal within two days. Penetrating corneal injuries are much more serious and the outcome will depend on the specific injury.