Vet Talk: Genetics and breeding can determine a dog’s eye health
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Annual or biennial eye checks are recommended for dogs in their senior years.
ST PHOTO: AZMI ATHNI
Gladys Boo
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SINGAPORE – Discovering that a beloved pet has a blinding eye disease can be devastating. Why does it have to happen? The answer lies in genetics.
As long as selective breeding for purebreds exists, the focus on desired traits will also lead to the selection of certain genetic mutations, hence the likelihood of inherited eye disorders.
Dog owners who understand the likelihood of the disease for their pups can keep a lookout for early signs to prevent an advanced onset of genetic diseases.
1. Cataracts
Many pet owners associate cataracts with old age. These are known as senile cataracts.
However, cataracts in dogs are most commonly inherited and affect more than 70 dog breeds worldwide. In Singapore, a large subset of my patients have sudden onset cataracts – occurring within days to weeks – that require emergency surgery. This is an unusual presentation compared with other parts of the world.
Likely breeds: Japanese spitz, miniature schnauzer, shiba inu, toy and miniature poodles
2. Glaucoma
Glaucoma is often called the “silent thief of sight” because it damages the eye and causes irreparable harm before there are any noticeable behavioural changes associated with blindness.
It can also cause extreme pain in dogs and cats. However, pet owners tend not to notice clinical signs until the disease is in advanced stages.
An eye examination by a board-certified ophthalmologist is necessary to identify optic nerve damage, not visible to the naked eye.
Likely breeds: American cocker spaniel, chow chow, Samoyed, shiba inu
3. Corneal ulcers
The outer, clear part of the eye known as the cornea can develop spontaneous ulcers due to exposure, irritation and trauma.
Corneal ulcers are painful and can become infected, and in the worst-case scenario, can lead to a corneal perforation, or rupture in the cornea.
Brachycephalic breeds have less corneal sensation and more prominent eyes, making them susceptible to corneal ulcers.
Likely breeds: French bulldog, Pekinese, pugs, shih tzu
4. Dry eye
Immune-mediated dry eye is an inherited disorder in dogs. It is a common eye condition resulting from inadequate production of tears by the lacrimal gland and/or gland of the third eyelid.
The patient often presents with thick yellow eye discharge in one or both eyes and has redness in the whites of the eyes.
Likely breeds: English bulldogs, cavalier King Charles spaniel, shih tzu, West Highland white terrier
5. Progressive retinal atrophy (PRA)
PRA is an inherited eye disease that leads to blindness in dogs. PRA is a non-painful condition that tends to progress slowly over time, often starting with a decreased ability to see well at night.
Likely breeds: Cocker spaniel, labrador, miniature schnauzer, toy poodle
Eye healthcare practice for pet owners
It is ideal to have your puppy checked by an eye specialist at six weeks of age and when it turns one. Subsequently, when your pet is in its senior years (small breed –10 years; medium breed – eight years; large breed – six years), annual or biennial checks are recommended. This way, pet owners can take a more preventative approach to eye health.
Pet owners should consult their general practice vet if they notice any redness in the whites of the eyes, grey/blue/white cloudy change in the eyes, squinting, tearing or eye discharge, lethargy (from eye pain), change in pupil shape or size, or vision loss (bumping into things).
The eye is a delicate organ and the treatment for most eye conditions to preserve vision is time-sensitive. Your general practice vet may refer your pet to an eye specialist if further diagnostics and treatment are needed.
The need for well-bred puppies
In countries with well-established specialists, breeders and new pet owners often pursue eye certificates to ensure they have a healthy puppy. It is important, as specialised eye care can be costly, especially if surgery is needed.
Furthermore, certain breeds are concurrently predisposed to multiple inherited eye conditions. For example, a shiba inu can have cataracts and be predisposed to glaucoma at the same time. There is a higher risk of such breeds losing their sight in the long term.
Active policing of genetic flaws in breeding will reduce the number of poorly bred puppies.
Over time, one can only hope that responsible breeders will obtain eye certificates from board-certified specialists for their breeding stock and try to eliminate certain genetic eye conditions in their breeding programmes.
This is similar to other certificates that prove the dogs are free from genetic health issues, such as musculoskeletal and heart conditions.
Dr Gladys Boo, a member of the Singapore Veterinary Association, is the only Board-Certified Diplomate of the American College of Veterinary Ophthalmologists in Singapore. She is based at The Eye Specialist For Animals.
Vet Talk is a fortnightly column where veterinarians offer advice on pet issues.
