What eye problems can occur in brachycephalic (flat-faced) dogs?
Recurrent damage to the surface of the eye (the cornea) leading to corneal ulceration is common in extremely brachycephalic dogs. Although corneal ulcers can result from many causes, including injury and reduced tear production, corneal ulcers in brachycephalic dogs are commonly due to a variety of anatomical changes seen in brachycephalic dogs compared to longer-muzzled dogs.
Why are some brachycephalic dogs prone to eye problems?
These changes include a shallow eye socket (that means that these dogs have prominent, ‘bulging’ eyes), eyelid abnormalities, and prominent nasal folds.
Effects on the eyes
Shallow eye sockets
The shallow eye socket means that many brachycephalic dogs cannot fully blink, which results in areas of cornea drying, especially in the centre of the eye.
Many brachycephalic dogs also have imperfect eyelid anatomy, as their eyelid opening is excessively wide, and their eyelids sometimes turn in (entropion) or out (ectropion). This can lead to further drying of the cornea, or damage due to contact with the eyelashes.
In some dogs, the nasal fold comes into contact with the cornea, causing direct damage due to rubbing of the skin (or hairs on the skin) with the surface of the eye.
Corneal ulcers are very painful and in some cases may progress and lead to extensive scarring of the eye surface which will impair vision, and in some cases require removal of the affected eye. Many of the same causes of corneal ulcers can also lead to corneal pigmentation in brachycephalic dogs, the appearance of brown or black deposits over the surface of the eye. This is usually as a chronic change over time, and although not thought to be painful, pigmentation may impair vision.
What are the signs my dog may have eye problems?
Corneal ulcers are extremely painful due to the number of nerve endings on the surface of the eye, and dogs with corneal ulcers will often show signs of eye pain. This may include:
- behavioural changes, such as squinting or an eye remaining closed
- excessive blinking
- sensitivity to light
- rubbing at the eyes with a paw
In addition, physical signs may include:
- cloudiness of the eye
- excessive watering
Because of the poor corneal sensitivity (brachycephalic dogs are less responsive to touch on their eye surface compared to longer-nosed breeds), brachycephalic dogs may not exhibit the usual clinical signs of corneal ulceration. This may lead to complications such as deepening ulceration and corneal perforation, sometimes resulting in loss of the eye.
What should I do if my dog shows signs of eye problems?
Irrespective of the underlying cause, corneal ulceration in brachycephalic dogs is always serious. The cornea has four layers, and how serious the ulcer is depends on how many layers of the cornea are involved. Corneal ulcers can develop and progress rapidly. If you notice any signs of corneal ulceration in your dog, immediate veterinary advice should be sought to avoid the ulcer deteriorating any further, which may threaten your dog’s eye.
How will my vet assess my dog?
Your vet will examine your dog’s eye and will use a dye to examine your dog’s cornea to diagnose whether an ulcer is present. They may also test your dog’s tear production using a tear test strip, and may take a swab to investigate any bacteria present on the surface of your dog’s eye.
What treatments will my dog need?
If an ulcer is diagnosed, your vet may offer analgesics (painkillers) to help manage your dog’s pain, and antibiotic therapy (usually eye drops) to fight any infection. Your dog may be given a collar to keep their paws away from their eyes while the ulcer heals. Your vet may also recommend long-term tear replacement therapy to combat corneal drying.
Will my dog need surgery on its eye?
Deeper, more serious ulcers may require surgical management, and your vet may refer you to a specialist ophthalmologist for this treatment. This may include corneal sutures, and conjunctival grafts or flaps.
What other surgery may be required?
For brachycephalic dogs with serious or recurrent ulcers, vets may recommend surgery to correct ulcer-causing anatomical problems, to reduce long-term damage to the cornea. This may include surgery to the eyelids to correct any areas where they roll in or out and, in some cases, removal or reduction of the nasal folds if they are in contact with the cornea. Some dogs suffer from refractory ulcers that are resistant to healing. In these cases, vets may recommend surgical removal of the eye, to avoid the long-term pain associated with chronic ulceration.
Breeding away from eye problems
The Kennel Club, British Veterinary Association and International Sheepdog Society offer breeders and owners the opportunity of screening for inherited eye disease by examination of the eye. Breeders can use the information obtained from the examination to eliminate or reduce the frequency of eye disease being passed on to puppies. Examination under the eye scheme is not restricted to the identification of inherited eye disease, but also includes general assessment of the health of the eye and adnexa (eyelids, tear ducts and other parts around the eye ball).
This article was written by Dr. Rowena Packer from the Royal Veterinary College who has given The Kennel Club kind permission to replicate it. Dr. Rowena Packer is a Research Fellow at the Royal Veterinary College. Her research interests include many areas of canine inherited disease including brachycephalic health and canine epilepsy.
Think your dog may be affected?
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