Ophthalmology - Special Services, Technology, & Information
The cornea is the clear outer layer of the eye. A corneal ulcer refers to disruption of the epithelium (surface layer) of the cornea.
Corneal ulcers may be caused by: exposure due to a large eyelid opening, irritation from eyelashes or an eyelid tumor, trauma to the eye, inadequate tear production, or other ocular diseases. Once the cornea is ulcerated, bacteria can multiply in the affected area and cause the ulcer to become much worse. If treated properly, minor ulcers often heal without complication. More serious ulcers may cause permanent scarring of the cornea or even progress until the eye perforates (ruptures). This is extremely painful and if left untreated, causes loss of vision and requires removal of the eye.
Some signs of a corneal ulcer include: pain and squinting, redness of the sclera (white part of the eye), tearing and discharge from the eye, and an abnormal appearance to the cornea. This abnormal appearance may include a bluish or white discoloration, blood vessels growing into the cornea, or a dark brown discoloration from pigment on the cornea. A veterinarian can detect a corneal ulcer by applying a fluorescent-green, non-toxic dye to the surface of the cornea. A careful examination of the eye is necessary to identify the underlying cause of the ulcer.
Corneal ulcers are treated differently depending on their cause, severity, and whether or not infection is present. Minor or superficial ulcers generally heal with topical antibiotics and a medication to dilate the pupil and relieve pain. Treatment may also include debridement of the ulcer. This means removal of the outermost layer of the cornea that is unable to attach to the deeper layers. This is a minor procedure and is done in the exam room with topical anesthetics and a cotton swab. More severe ulcers that are in danger of causing perforation of the eye are generally treated surgically by placing a graft over the corneal ulcer. These grafts are generally taken either from the conjunctiva (conjunctival graft or flap) or cornea from a donor animal. If these more serious ulcers heal successfully, they generally leave a whitish scar on the cornea, which may interfere with vision in that eye. It is critical to identify and treat any underlying cause for the corneal ulcer, or it may worsen or recur.