When scratches create further problems The cornea is the clear front window that covers the colored portion of the eye. A corneal erosion or abrasion refers to a scratch or injury to the outer layer of the cornea. Common causes of these painful abrasions include contact lenses, a baby’s fingernail, tree limbs, bushes or vigorous rubbing of the eye. The most common treatment for corneal erosions is to patch the eye tightly. An antibiotic may be prescribed to prevent infection. A corneal erosion usually heals within a week. If bacteria get into the tissues under the protective layer of the eye a corneal ulcer can occur. These complications can be very serious and cause loss of vision. Proper care by you and your doctor is necessary to prevent serious consequences.