What Are the Causes of Blindness in Dogs?

Regularly inspect the condition of your dog's eyes.
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Like humans, dogs can lose their sight, either through disease, old age or injury. Many potential causes of blindness are treatable, if detected early. Unlike humans, dogs are much better at adapting to their limitations. Because dogs can’t grasp the concept of mortality and disease, they typically soldier on, adjusting their habits and behavior quickly. There are ways you can help too.


If left untreated, glaucoma will cause permanent and irreversible blindness in your dog. Glaucoma is caused by a higher-than-normal amount of pressure applied to the optic nerve. This results in insufficient drainage of the eye fluid. Symptoms, which may be mistaken for the less serious condition of conjunctivitis, include cloudiness, redness and heavy discharge. Owners of Samoyeds, chow chows, poodles, cocker spaniels and Siberian huskies should be particularly alert to the symptoms, as these breeds are at higher risk. Your veterinarian will typically opt to prescribe a course of drugs that bring the pressure on the optic nerve down to a normal level, in order to manage the condition and stem the damage caused to the eye.


Also known as “soft eye,” this condition is caused by an inflammation of the iris. Symptoms include redness, squinting, impaired vision and fluid leakage. Uveitis is typically associated with other bacteria infections and is most likely to occur in the aftermath of other trauma to the eye, such as a retinal injury. Your veterinarian will use a combination of immunosuppressants and steroids to address the cause and the symptoms.

Progressive Retinal Atrophy

Sadly, this inherited disease is untreatable, so there is much focus on identifying sufferers early and then ensuring they don’t mate and pass the condition along. PRA is painless, but is almost certain to result in complete blindness, unless onset occurs late in life and the dog passes away due to old age before the disease can take full hold. Often, the first symptom of PRA is a distinctive “glow” to the eye. If your dog develops PRA, your focus must be on assisting him to make the best of life. You can do this by ensuring there are no physical obstacles around the home that he may bang into, using sound to communicate, never sneaking up on him and avoiding altering the layout of his environment. You might just be amazed at how quickly and bravely he adapts to the loss of vision.

Eye Tumors

Most eye tumors are benign, meaning they will not spread and are not cancerous, although it’s always best to get veterinary confirmation of this. Although benign, eye tumors pose a high risk of causing blindness if untreated. Typically originating just behind the iris, these tumors most likely require surgical removal.


Nutritional deficiencies during puppyhood, old age, diabetes and pure bad luck due to genetic disposition can all cause cataracts. Although associated with old age, cataracts can occur at any age. In fact, cataracts caused by age-related degeneration are typically less serious and less likely to cause complete blindness than cataracts brought on by other causes. Cloudiness and impaired vision are the two defining symptoms. Cataracts don’t cause pain and don’t pose a wider health risk, so your vet will consider your dog’s age, lifestyle and the extent of vision loss before deciding whether or not to operate.