The first type to discuss is in older patients:
Indolent Corneal Ulcers
General Information
Normally, large superficial ulcerations should heal completely in 5 to 7 days with minimal scarring. Indolent ulcers, however, can take six months to a year to heal without treatment. Excessive corneal vessel infiltrate and scarring may occur without treatment. Scarring may be severe enough to permanently limit vision in the affected eye. This type of ulcer commonly effects middle-age to older dogs, and Boxers are overrepresented.
Symptoms
Increased tearing
Squinting
Frequent Blinking
Corneal haziness
Redness
Cause
Initially, an underlying cause for the ulcer (such as trauma, a foreign body under the third eyelid, or abnormal eyelashes) must be ruled out.
Although the exact reason indolent ulcers occur is unknown, dogs with this condition present with an abnormal layer in the superficial (upper) corneal stroma (2nd layer of the cornea). This abnormal layer is thought to prevent normal adhesion of the epithelium to the stroma below; simply the corneal cells have nothing to adhere to.
Simply blinking the eyelids may aggravate the epithelium to pull away from the abnormal stroma causing an ulcer.
Treatment
Several treatment methods exist for indolent ulcers, with the same idea in mind. Initially, the treatment involves rubbing the loose epithelium off with a cotton swab (debridement). Following debridement, a procedure to either remove the abnormal layer of the superficial stroma or a procedure to cut through the abnormal layer to give the epithelium specific places where it can stick down, is performed. Removal of the abnormal layer of the stroma can be performed with a diamond burr, which is similar to a tiny Dremel tool. The burr is specially designed for the eye and treats the entire cornea. The diamond burr procedure result in less scarring than other treatment methods. Another procedure, termed a grid keratotomy or anterior stromal puncture, involves making tiny scratches or pricks through the abnormal stromal layer with a blade or needle. After the procedure, one to two topical eye drops are recommended alongside oral pain medications.
Bandage Contact Lens
To aid in comfort, a bandage contact lens may be placed. This soft lens does not have any healing properties, but does show to help improve discomfort after the procedure. These will stay in place on their own and be removed at the follow up appointment.
Prognosis
Our goal with treatment is to heal the ulcer quickly and prevent scarring. Typically, the ulcer will heal within 2-3 weeks. Rarely, a second procedure may need to be performed if the indolent ulcer has not healed. Approximately 50% of dogs that develop an indolent ulcer in one eye will later develop it in the other eye.