Pigmentary keratitis occurs most often in brachycephalic dogs, like Pugs, although it can be seen in other breeds. In simplest terms, pigmentary keratitis is the buildup of melanin or pigment on the surface of the cornea. The pigment will appear brown or black. It can build up enough to block vision.
Unfortunately, the conformation of brachycephalic breeds predisposes them to several health conditions, including ocular ones like pigmentary keratosis. Genetics may also be at work.
What Causes Pigmentary Keratitis in Dogs?
Irritation to the cornea stimulates the pigment deposits. This can be caused by eyelids that roll in, so the eyelashes or hairs rub on the cornea. It can be caused by eyelids that droop, allowing dust and plant material or irritate the cornea. In some cases, irritation is caused by abnormal eye lashes.
Less commonly, direct trauma to the cornea or the rubbing of even benign eyelid tumors may stimulate pigment production. Anything that interferes with blinking or tear production may also lead to corneal damage and pigment production.
The short muzzles of brachycephalic dogs, often with nasal skin folds, mean the hair is closer to the eye. The large, round eyes are open to irritants, including things like blowing dust.
Diagnosing Pigmentary Keratosis in Dogs
Your veterinarian can usually diagnose pigmentary keratosis during a routine office visit, but some vets may suggest referral to a veterinary ophthalmologist for the latest in treatment. Often, a fluorescein stain of the cornea will be done to check for any corneal ulcers that might accompany the pigmentary keratitis as that would mean adjustments in medications.
Can You Treat Pigmentary Keratosis in Dogs?
Many cases of pigmentary keratitis are managed medically. That means eye drops or eye ointments, often multiple times a day. Be sure to follow dosing directions exactly. Immunosuppressive drugs such as cyclosporine or tacrolimus are fairly standard. Artificial tears, as drops or ointments, may be added if your dog also has “dry eye” or a lack of tear production called keratitis sicca.
Along with medical therapy, surgical treatment may be suggested. This surgery is done on the eyelids to correct an eyelid that turns in (entropion) or droops outward (ectropion) or to remove abnormally located eyelashes. Excessive skin folds may be removed. Those corrections would prevent the constant irritation to the cornea. Your veterinarian may perform these surgeries themselves, or they may refer you to a veterinary ophthalmologist.
Preventing Pigmentary Keratitis in a Dog
Can you prevent pigmentary keratitis? Not really. When choosing a puppy, try to pick one with a less extreme “flat” face and search for breeders with more moderate dogs. If your dog has an extreme brachycephalic face, he will be prone to this eye disease.
If you notice any pigment moving onto the cornea, have it evaluated early on before any permanent visual damage is done.
Try to avoid dusty conditions. If you have fans blowing to keep your dog cool, mop or vacuum to reduce dust. Avoid fields during dusty and dry conditions or that have lots of plant material that could irritate the cornea.
