Cataracts are seen in people as well as dogs. They can occur in puppies or adults and vision loss is the main concern surrounding them. Treatment options are limited but effective and some disease management may also be available depending on the type of cataract that is present. Knowing the signs of cataracts, what causes them, and how they are treated or managed can help you get your dog the help it may one day need.
What Are Cataracts?
The eye is made up of multiple parts and the thick clear part of the eye behind the cornea and colored iris is called the lens. The lens is made up of protein and water and reflects light onto the retina to allow a dog to see. If the lens becomes damaged or unable to reflect light, vision loss occurs. Cataracts are changes in the lens of the eye that causes it to become cloudy or milky in appearance. This cloudiness blocks the light from adequately entering the eye and therefore negatively affects a dog's sight. Cataracts are defined by how much of the lens they are blocking and four types exist.
- Incipient cataracts - This smallest type of cataract covers less than 15% of the lens.
- Immature cataracts - These cataracts can cover 15-100% of the lens but a tapetal reflection is still present to allow some light to reflect onto the retina.
- Mature cataracts - Also known as fully developed cataracts, mature cataracts cover 100% of the lens and no tapetal reflection is present.
- Hypermature cataracts - In addition to covering 100% of the lens and not allowing a tapetal reflection, resorption of the lens is seen in hypermature cataracts. This appears as a sparkly area in the lens and lens wrinkling as well as uveitis may also be present.
Cataracts typically become more mature over time but in some young dogs, they can regress and disappear. Cataracts are not the same as lenticular or nuclear sclerosis. This eye issue can also occur in adult dogs and creates a cloudiness to a their eyes.
Signs of Cataracts in Dogs
Signs of Cataracts in Dogs
- Cloudiness or opacity in the eye
- Bumping into things
The only real sign that a dog has a cataract forming is if you see a cloudiness in your dog's eye. A change to the normally clear lens in the center of the colored iris is usually described as being milky or cloudy. This cloudiness can cover just part or all of the lens. When all of the lens is covered by a cataract, blindness a dog may become blind and a dog may bump into things that it used to be able to see. Cataracts are not painful but they can be a result of an underlying issue.
Causes of Cataracts
Some dogs are born with cataracts but many dogs develop them as adults. There are a variety of reasons why cataracts can form. Some of these causes include:
- Genetics - The most common cause of cataracts in dogs is genetics. These cataracts are referred to as inherited cataracts even though they may not show up until a dog is an adult.
- Diabetes mellitus - Diabetes is the second most common reason why a dog develops cataracts. If excess sugar is present in the eye fluid, more water accumulates and results in cataracts.
- Trauma - Severe damage to the lens of the eye can result in the formation of a cataract.
- Retinal disease - While not common, late stage retinal degeneration can cause cataracts in dogs.
- Uveitis - If a dog has inflammation inside its eye, this is called uveitis, and cataracts may result.
- Age - With age comes age-related changes that can contribute to cataract formation.
Diagnosing Cataracts in Dogs
If you suspect your dog has a cataract, a full eye examination should be performed by a veterinarian. Sometimes a vet that specializes in opthamology will be recommended to be seen by your regular vet due to the extra equipment they have to examine eyes. Special lamps and lens may be used to visualize parts of your dog's eyes and rule out other eye changes and concerns like corneal ulcers or lenticular sclerosis. The location and cause of the cataract as well as how much of the lens is affected by the cataract will determine how much vision your dog may or may not have and whether surgery is recommended to remove it.
Treatment of Cataracts in Dogs
While cataracts are not painful or life-threatening, in order to restore your dog's vision and get rid of the cataract, surgery is widely considered to be the only proven treatment option. Not all veterinarians will perform cataract surgery, and the cost may be prohibitive for some dog owners, but it is curative. Eye drops to prevent infection and inflammation post-operatively are normally prescribed but a dog will regain sight after the cataract is removed. Regular eye exams will be also be needed after surgery to continually monitor the health of the dog's eye.
In some dogs with immature cataracts, eye drops to dilate the eye may be used to enhance your dog's vision. Vitamins, antioxidants, and various supplements are available to support eye health but will not make a cataract disappear. Some may also lack scientific evidence of efficacy. One product called Kinostat has shown some promising results to delay cataract progression. It is only for diabetic dogs and requires life long administration to help prevent the progression of cataracts but will not dissolve them.
As with any product, you should always consult your veterinarian prior to administering anything to your dog. Some products may interact with other things your dog needs to take and could cause more harm than good.
How to Prevent Cataracts in Dogs
It can be nearly impossible to prevent cataracts from forming in your dog's eyes. Avoiding eye trauma and things that can contribute to the development of diabetes can decreaes the likelihood of cataracts but genetics cannot be stopped if your dog has inherited cataracts. Breeding should be avoided in dogs that have cataracts to decrease the chances that their offspring will develop them later in life.
At Risk Breeds for Developing Cataracts
Some breeds of dogs can be more effected by hereditary or inherited cataracts than others. While some of these breeds are affected at birth or as puppies, many don't develop noticeable cataracts until they are adults. Over 150 breeds are at risk for developing inherited cataracts and include:
- American cocker spaniel
- Afghan hound
- Australian shepherd
- Bichon frise
- Boston terrier
- Chesapeake Bay retriever
- Entelbucher mountain dog
- Golden retriever
- German shepherd
- Labrador retriever
- Miniature schnauzer
- Norwegian buhund
- Siberian husky
- Staffordshire bull terrier
- Standard poodle
Urfer SR, Greer K, Wolf NS. Age-related cataract in dogs: a biomarker for life span and its relation to body size. Age (Dordr). 2011;33(3):451-460. doi:10.1007/s11357-010-9158-4
Davidson MG and Nelms SR. Diseases of the Canine Lens and Cataract Formation. In Gelatt KN (ed): Veterinary Ophthalmology 4th Pg 859-887. Blackwell Publishing, Ames IA.