“Brachycephalic” is the medical term to describe short-nosed breeds of animals. There are brachycephalic breeds of both cats and dogs. Examples include: the Pug, Boston Terrier, Pekingese, Boxer, Bulldog, Shih Tzu, Bulldogs, Boxers, Persian, Himalayan, Burmese. Brachycephalic breeds are unique in both their outward appearance and their inward anatomy. The anatomy around the eye is also unique and deserves attention from the pet owner. This article explains several of the more common eye conditions in the brachycephalic breeds we treat as veterinary ophthalmologists.
With most of the nasal bones compacted into a small space, brachycephalic animals exhibit differences with the way their eyes are positioned in their skull vs. other breeds. The prominent eyes of these pets is due to the shallow bony orbit. Any trauma to the head can cause an eye to dislocate from the orbit (proptosed eye) and require surgical replacement. Excessive strain on the neck with a neck collar or lead could predispose some animals to this condition. The eyes of the brachycephalic patient may be so prominent that the eyelids cannot close all the way over the eyes during a normal blink. This will lead to irritation and drying of the center of the eye (cornea) unless surgical correction is performed or topical lubricants are applied to the eye.
Eyelid problems are common in the brachycephalic animals. Excessive tearing is a common finding in these breeds. For some companions, the shape of the eyelids prevents normal tear drainage and tears overflow onto the eyelid margins, nasal folds and face. This problem does not cause discomfort; however, there is a more serious condition which may cause excessive tearing. Entropion is a condition that involves inward rolling of the eyelids such that the lashes and periocular hair rub on the eye and cause excessive tearing. Surgery may be needed to correct this problem as it may lead to painful corneal ulcers. Distichia and ectopic cilia are eyelid abnormalities that involve abnormal growth or positioning of the eyelashes. In some cases, these abnormal hairs may rub the eye and cause irritation. Distichia and ectopic cilia are corrected with surgery. Trichiasis is normal hairs growing in an abnormal direction. They are often noted near the inside corner of the eye and may “wick” tears onto the face or cause chronic irritation. Euryblepharon and macroblepharon refer to dogs with sagging eyelids or abnormally large/long eyelid margins.
The cornea is the clear outer surface of the eye. Chronic irritation to the surface of the eye may lead to the deposition of pigment or scar tissue on the eye surface, often near the portion of the cornea near the nose. This condition is called pigmentary keratitis. This pigment may be difficult to see without a bright light but if it is noted, a search for the cause is warranted. Pigmentary keratitis may be an indicator of irritation due to dry eye, entropion, distichia, ectopic cilia or reduced blinking. Depending on the location of the pigmentation, surgery or long term anti-inflammatory and lubricating eye medications may be recommended. Many brachycephalics animals have normal tear production but poor quality tears. As tears are important in maintaining corneal health and clarity, a poor quality tear film will cause corneal irritation, scarring and discomfort. Topical lubrication is recommended to help moisten the ocular surface for this condition. Brachycephalic dogs are especially prone to corneal ulcers (cut/scratch) due to their short nose and eye prominence. We often say their eyes serve as their “bumpers” as small brachycephalic dogs often scratch their eyes in bushes, while playing and due to a visit from the neighborhood cat! Corneal ulcers are painful erosions on the surface of the eye and require immediate medical attention. Corneal ulcers are treated with topical eye antibiotics and in severe cases, surgery may be recommended.
Dry eye (keratoconjunctivitis sicca or KCS) is another common condition in the brachycephalic breeds. Dry eye is caused by a lack of tear production and causes increased mucus, redness, clouding, reduced vision and painful corneal ulcers. When the surface of the eye is dry, the conjunctiva (white spongy membrane around the eye) produces excess mucus as an adaptation to help protect the eye. Dry eye requires lifelong therapy as there is not “cure”. Medications are prescribed by the veterinarian to help stimulate tear production, reduce surface inflammation and help maintain eye lubrication.
What Should We Watch For In Our Brachycephalic Breeds?
Any of the clinical signs noted below may indicate that your pet has an eye problem and immediate care from a veterinarian is recommended.
- Red eyes
- Reduced vision
- Cloudy eyes
- Eye opacities (white, gray, black, red)
- Squinting (indicates eye pain)
- Excessive tearing
- Rubbing of the eyes
- Obvious defect on the surface of the eye
Michael H. Brown, DVM, MS, Diplomate ACVO