Cataracts are relatively common in dogs and may occur for a few different reasons. When cataracts form, they can lead to blindness. Surgery is sometimes necessary to remove cataracts in dogs and restore vision.
What are Cataracts in Dogs?
A cataract is an opacity of the lens in the eye. The intraocular crystalline lens is made of transparent fibrous tissue and located behind the iris. In a normal eye, this transparent lens enables light to pass through the eye to the retina in order to create a clear image. When the lens becomes opaque due to cataract formation, some or all light will be blocked and the vision of the dog becomes compromised. A cataract often starts out as a small spot of milky white cloudiness and grows until it causes complete blindness.
Cataracts typically get worse over time, progressing from immature to mature. A mature cataract involves the entire lens and completely obstructs vision. Cataracts may cause lens luxation, meaning the lens is displaced and can cause harm to the other parts of the eyes. In time, cataracts may begin to dissolve, leading to painful eye inflammation.
Note that the lenses of dogs' eyes will change as they age. The fibrous tissue contracts and causes some cloudiness to the eyes. This is a normal part of aging and does not necessarily mean the dog is developing cataracts. Only a veterinarian can determine the presence of cataracts after doing an eye examination.
Signs of Cataracts in Dogs
- Cloudy appearance to eyes
- Loss of vision
Causes of Cataracts in Dogs
Cataracts can be considered primary or secondary. Primary cataracts occur for no known reason other than genetic predisposition. Secondary cataracts are due to some type of problem in the body or the eye itself.
Primary cataracts in dogs are caused by genetics. They may be present at birth (congenital) or develop when the dog is still a puppy (juvenile cataracts). Dogs that develop cataracts as adults or seniors may also have a genetic predisposition.
Certain dog breeds are known to be predisposed to cataracts. At-risk breeds include, but are not limited to, American Cocker Spaniels, Bichon Frise, Boston Terriers, Poodles, and Miniature Schnauzers.
Cataracts not caused by genetics are generally called secondary cataracts. They develop when there is a problem in the eye that leads to their formation. Potential causes include trauma to the eye, eye inflammation, progressive retinal atrophy, nutritional deficiencies, inflammation in the eye, endocrine diseases, and metabolic disorders.
Diabetes mellitus is a very common cause of cataracts in dogs. The lens of a normal eye absorbs glucose from the body to use as energy. Excess glucose is converted into a sugar called sorbitol. If there is too much glucose, then too much sorbitol will be produced. Sorbitol draws water into the lens, leading to cataract development.
How to Detect Cataracts in Dogs
If you notice cloudiness in your dog's eyes, it doesn't necessarily mean cataracts are present. Only a veterinarian can diagnose cataracts in dogs after performing an eye exam. Age changes and other conditions may cause cloudiness of the eyes and even loss of vision.
If cataract formation is seen in one or both eyes on examination, your vet will assess the size and severity, plus look for other eye problems. Recommendations are based on the severity of cataracts, the condition of the eye, the level of vision loss, and the dog's overall health and quality of life.
Contact your vet if you notice eye cloudiness or vision loss in-between routine vet visits. Because cataracts may start small and get worse over time, early detection can help you prepare for treatment down the road.
Be sure to bring your dog to the vet for routine wellness check-ups every six to 12 months (or as recommended by your vet). An immature cataract may be found during a routine exam even if it cannot be seen with the naked eye.
Cataract Treatment for Dogs
Surgery is the only way to actually remove a cataract. There are no medications that can effectively treat, prevent, or slow progression. However, your vet may recommend certain eye drops or systemic medications to treat the secondary effects of cataracts.
Cataract surgery is done by a board-certified veterinary ophthalmologist using advanced equipment. The affected lens is carefully removed and an artificial lens is placed in the eye.
Recovery from surgery usually takes a few weeks, during which your dog must wear an E-collar to prevent rubbing of the eye. Anti-inflammatory and/or antibiotic eye medications may be used to support healing. Most dogs recover well and experience partial or complete restoration of vision.