By Dr. Becker
Most veterinary offices receive calls now and then from a concerned client whose dog’s eyes have turned blue.
There are actually several conditions that can create a blue haze that partially or completely covers the front of the eye, including the following five.
5 Diseases That Cause Blue Eyes in Dogs
1. Nuclear sclerosis. Nuclear sclerosis, also called lenticular sclerosis, can cause the pupils of your dog’s eyes to take on a cloudy bluish-gray appearance. The condition is also seen in humans and horses.
This condition is a normal change to the lenses of the eyes that typically occurs in dogs over the age of six. It usually develops in both eyes at the same time, and the good news is, it isn’t painful. Because nuclear sclerosis comes on gradually, your dog should be able to comfortably adapt to any minor changes in vision that occur.
2. Cataracts form a blue cloud of varying degrees inside the capsule that holds the lens of the eye. Cataracts can progress very slowly over many years or they can come on very quickly, leading to blindness within a few days or weeks.
Cataracts in dogs are often inherited. They can also be caused by diabetes, toxicity from drugs and pest preventives, another underlying eye disease, trauma to the eye, nutritional deficiencies in puppies, and as part of the aging process.
If your dog is diagnosed with cataracts, less troublesome ones will be rechecked periodically to see if they're progressing. Sometimes anti-inflammatory eye drops are prescribed. But if your pet's vision is affected, her quality of life is compromised, or the cataracts are progressing rapidly, surgery is sometimes recommended to restore vision.
3. Glaucoma is a condition in which there is increased pressure within your dog’s eye. The fluid produced inside the eye isn’t draining properly, which causes a buildup of painful pressure within the eye. If the fluid buildup (which is what causes the cloudy blue appearance) and pressure are left untreated, they will cause the eye to enlarge and become misshapen, and the eventual result will be irreversible blindness.
In pets, glaucoma is either primary or secondary. Primary glaucoma is inherited and typically starts in one eye, but in most cases it will eventually involve both eyes. Secondary glaucoma occurs when other eye diseases are present, including uveitis, advanced cataracts, cancer of the eye, lens displacement, and chronic retinal detachment.
Treatment will depend on the cause and severity of the disease. But the goal is always to alleviate the pressure inside the eye as quickly as possible by reducing the production of aqueous humor and increasing drainage from the affected eye. Unfortunately, medical treatment of the condition is not nearly as successful with pets as it is with people. Long-term control of primary glaucoma in a blind eye is usually removal of the eye. As awful as it sounds, it actually provides the very best relief for the dog.
4. Corneal dystrophy. Corneal dystrophy is an inherited, progressive condition that usually affects both eyes. Fortunately, it isn’t painful, and normal vision may not be affected. There are three types of corneal dystrophy, depending on the location: epithelial corneal dystrophy, which affects cell formation; stromal corneal dystrophy, which causes the cloudy blue appearance; and endothelial corneal dystrophy, which affects the cells of the lining of the cornea.
Stromal corneal dystrophy usually does not require treatment. Endothelial corneal dystrophy is sometimes treated with contact lenses over the eyes. Epithelial corneal tags, when present, may be removed. Another treatment option for endothelial corneal dystrophy is flap surgery of the conjunctiva. Corneal transplants are performed occasionally, but the results are inconsistent.
A dog with corneal dystrophy will usually have some eye cloudiness even after successful treatment of the condition. And since corneal ulcers are common with both endothelial and epithelial corneal dystrophy, dogs with pain or blinking or watering of the eyes should be seen by a veterinarian.
5. Anterior uveitis. If your dog has anterior uveitis, it means there is inflammation of the iris and ciliary body within the uvea of the eye. The disease is also known as iridocyclitis, and it is a quite painful condition that can ultimately threaten a dog's vision.
Because of the uvea's rich blood supply, it's a natural target for problems that originate in other parts of a dog's body. Uveitis is a common secondary condition that results from a disease process elsewhere in the body.
Anterior uveitis causes pain in the eyes. There may also be squinting, pawing at the eyes, eye redness, excessive tearing or discharge, change in the appearance of the pupil, change in the shape or color of the iris, swelling of the eyeball, or a dull or cloudy-looking eye.
Treatment options will depend on the diagnosis. The condition should be treated aggressively to prevent further damage to the eye. In every case, regardless of the cause of uveitis, eye drops and ointments are prescribed, along with medications to manage pain and inflammation. If an infection is present, the appropriate medication will be prescribed. Very rarely, surgery to remove the eye is necessary to resolve an underlying tumor that's causing secondary disease like glaucoma.
If you notice your dog’s eyes are becoming cloudy or taking on a bluish tint, it’s very important to make an appointment with your veterinarian. Some conditions that cause blue eyes are harmless, painless, and have little or no effect on a dog’s vision. But I recommend you have your canine companion’s eyes examined as soon as possible to determine exactly what’s going on, and whether treatment is needed.