Cataracts are essentially an abnormal cloudiness of the lens of the eye; usually caused by proteins that clump together so that the lens becomes opaque over time.
Cataracts prevent light passing through the lens and reaching the retina at the back of the eye which is where images are normally formed giving sight. A cataract may be a small speck in the eyes’ lens, that hardly interferes with vision, or a much more severe larger problem affecting the whole lens and so causing blindness.
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Do dogs get cataracts?
YES! Cataracts are one of the most common causes of sight loss in dogs and frequently lead to blindness. Fortunately, dogs are very good at adapting to their environments and so often cope very well with developing cataracts. However, this can delay owners picking up their dog forming them especially in the earlier development stages which can lead to delayed diagnosis and treatment.
What causes cataracts in dogs?
Causes include genetic inheritance, metabolic disturbances such as diabetes, older age, trauma or injury, malnutrition, other eye diseases leading to inflammation within the eye and chronic uveitis (an inflammatory disease of the eye).
Inherited causes
Certain breeds of dogs inherit a high risk of developing cataracts; such as Golden Retrievers, Miniature Schnauzers, West Highland White Terriers and Old English Sheepdogs. Some puppies are born with cataracts, this is called congenital cataracts. And others develop them later in their adolescent years or when they are middle aged.
Dogs affected by hereditary cataracts should not be used for breeding as they are highly likely to pass this eye disease on to their puppies. The British Veterinary Association, Kennel Club and International Sheep Dog Society screen adult dogs for breeding under the Eye Scheme to ensure that puppies are protected from being bred by parents with the condition and so developing it themselves. It is prudent to discuss screening with breeders when you are looking for a new puppy if you are considering a breed that is at high risk of cataract development.
Metabolic disturbance e.g., Diabetes
Diabetes is a considerable risk factor for developing cataracts. In this case cataracts are caused by excess blood sugar (glucose) in the lens which in turn draws water into the lens causing it to swell; disrupting its structure and causing it to become cloudy.
The cataracts tend to form quickly. They frequently lead to secondary problems from the lens swelling, such as uveitis and glaucoma which are painful to your dog.
Trauma
Any injury to the eye such as a penetrating injury whereby a foreign object enters or pierces the eye or a concussion to the eye can lead to inflammation and swelling of the eye and in turn this affects the lens causing it to become cloudy. Those more prone to corneal (eye surface) ulcers such as brachycephalic (short – nosed) breeds have a higher chance of developing both traumatic and chronic uveitis leading to cataracts.
Chronic uveitis
With long-term inflammation within the eye, the lens continuously degenerates causing inflammatory changes within it that leads to the development of lens opacity and cataracts.
Nutritional imbalances
Although rare nowadays due to advances in canine nutrition and the availability of complete formulated diets, malnutrition, or improper nutrition particularly at early life stages can lead to a disturbed vitamin and essential amino acid levels causing cataracts.
Age Cataracts
It is possible for cataracts to develop simply because of aging, we call these senile cataracts. Senile cataracts often develop slowly and cause a gradual loss of vision. BUT careful not to mistake the bluish greying of the dogs’ lens seen in nuclear sclerosis as cataract development.
In older dogs the lens fibres can become compressed and degenerate over time. This is a common and normal process of aging and doesn’t lead to blindness; dogs just may not see fine details like they once did.
Will my dog develop cataracts?
Being a responsible pet owner, you can only do your best to ensure the health of your new puppy. Be careful to select a breed that is not at higher risk of developing cataracts. Or discuss screening of parent dogs with breeders of high-risk breeds. React quickly to any injuries involving your dogs’ eyes as they happen, which is important anyway to make sure your dog is comfortable and keeps their vision in the short and long term.
Is it painful to have cataracts?
Cataracts themselves aren’t usually painful. But some of the underlying conditions that cause them are (such as eye injury or glaucoma). Cataracts can also lead to other conditions of the eye including lens-induced uveitis (eye inflammation), glaucoma (increased pressure within the eye), and lens luxation (dislocation of the lens) all of which are painful.
What should I do if I suspect my dog is developing cataracts?
If you notice a change in the appearance of your dogs’ eyes or notice them bumping into things more, especially at night, this could be early signs of cataract development and you should seek veterinary advice. The quicker you seek veterinary help, the better the outcome is likely to be for your dog. Earlier intervention has shown more success. And it allows you to support your dog and plan treatment or make provisions for your dog more easily.
What can be done if my dog develops cataracts?
If your dog’s cataracts have been caused by trauma or an underlying condition, that needs to be treated first but this will not cure your dog of cataracts. The only way to get rid of cataracts is to remove them.
The only effective vision-restoring treatment for cataracts is surgery, which is performed under general anaesthesia. The main reasons people consider cataract surgery for their dogs is to regain their dog’s sight so they can enjoy moving around and playing again, and to avoid the complications from cataracts that can lead to pain.
Cataract surgery is called phacoemulsification.
This technique uses special equipment to remove material inside the lens with the goal of inserting an artificial lens. Most of the time it is possible to replace the lens with an artificial one. However in the cases where the lens is removed and not replaced your dog will be far-sighted but able to see. At home care is quite intensive post operatively with dogs requiring life-long medication to keep the eyes comfortable and visual. And regular follow ups with a specialist ophthalmologist veterinarian to optimise results.
If phacoemulsification isn’t possible for your dog but their cataracts clearly cause discomfort, pain and a reduced quality of life, it may be considered within their best interest to remove the eye altogether in a procedure called an enucleation. An enucleation removes the whole eye surgically under general anaesthetic. This procedure is most appropriate in dogs where trauma / injury has caused only one eye to be affected rather than those with conditions where both eyes are likely to be affected like those with diabetes. Dogs generally cope very well with only a single eye and are relieved by no longer experiencing the discomfort of eye disease they previously did.
If your dog has been diagnosed with cataracts, talk to your vet about your dog, and decide on the best course of action, developing a treatment plan together that gives your dog the best outcome.
References:
- Canine cataracts – Cornell University College of Veterinary Medicine
- Cataracts in dogs – PDSA
- Canine cataracts – RVC
- Disorders of the Lens in Dogs – MSD Veterinary Manual
- Table: Inherited Cataracts in Dogs – MSD Veterinary Manual
- Cataract for dogs – Vetlexicon Canis
- Urrets-Zavalia syndrome following cataract surgery in dogs: A case series
- Nutritional Lens Opacities in Two Litters of Newfoundland Dogs | The Journal of Nutrition | Oxford Academic
- Is It Possible for Dogs to be Short-Sighted?
- Effect of oral antioxidants on the progression of canine senile cataracts: a retrospective study
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