Cloudy With a Chance of Cataracts
Here’s how to spot the eye condition and help your dog see more clearly.
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When you look into your dog’s eyes, what do you see? Besides the one true object of their desire: that peanut-butter treat you’ve been hiding from them on top of the fridge. If your dog is healthy, you should see bright, shiny, clear eyes looking back at you. But if your dog’s eyes look a little cloudy or bluish-gray, it could mean that cataracts (clouded-eye lenses) are forming. Cloudy eyes don’t always indicate cataracts, but you shouldn’t ignore them — it’s best to take your dog to the vet to be checked out for canine eye disorders. In the meantime, keep reading to learn everything you need to know about cataracts in dogs, including how to treat them.
What Are Cataracts, Exactly?
Cataracts in dogs are characterized by opacity in the lens of the eye (basically, a cloudy film keeps light from entering the eye). The lens is the normally clear structure that sits directly behind the iris (the colored part of the dog’s eye), and its job is to focus light as it moves toward the back part of the eye (the retina). Despite its clarity, the lens is, in fact, made of tissue fibers. As a dog ages, these fibers become more dense and compact, preventing the passage of light to the retina, leading to blindness.
What Causes Cataracts in Dogs to Develop?
Cataracts in dogs are usually hereditary. Other causes include congenital (a dog who is born with it), senile cataracts (age-related), diabetes, trauma, dietary deficiency (milk replacement formulas that are low in arginine or phenylalanine have been implicated as well as puppies fed strictly evaporated milk formulas or goats milk), electric shock, or toxins.
Why Are Cataracts in Dogs Harmful?
A cataract by itself does not necessarily require treatment. If the only problem is blindness, and there is no associated inflammation or glaucoma, you could leave it alone. Blind dogs can have an excellent quality of life and can adjust well to vision loss (though it’s important not to move furniture around or leave any hazardous clutter around the house). Some dogs, however, do become anxious — or even aggressive — when they lose their vision.
A bigger concern is that a cataract can luxate, meaning it can slip from the tissue strands that hold it in place and end up floating around in the eye, causing damage. On top of that, if a cataract settles in a place blocking the natural fluid drainage of the eye, they can get a buildup in eye pressure (glacoma), leading to pain and permanent blindness. Another problem is that cataracts can begin to liquefy and dissolve after a long time. While this sounds like it should be a good thing, it is a highly inflammatory process, and it creates a condition called uveitis. This is a very painful eye disease that can also lead to glaucoma.
How Are Cataracts in Dogs Treated?
Cataract treatment for dogs generally involves surgical removal or physical dissolution (“breaking up”) of the cataract under anesthesia. The ideal time for cataract surgery is the immature or early mature cataract stage. Of course, your dog must also be in good general health to undergo treatment. For example, a diabetic dog must be well regulated before cataract surgery. Also, in order for a dog to be a good surgical candidate, they must also have a temperament conducive to having eye drops administered at home. Lab work is performed prior to anesthesia and some ophthalmologists also request that pets have their teeth cleaned prior to surgery to minimize sources of infection in the eye.
Historically, removing the cataract meant surgically cutting into the eye and physically removing the lens. This is still done for older patients whose lenses are compact, but for younger patients where the lens is still soft, a technique called phacoemulsification is preferred.
Phacoemulsification has become the most common method of removing cataracts in dogs. With phacoemulsification, the lens is broken apart by sound waves and sucked out with a gadget similar to a tiny — a few millimeters wide — vacuum cleaner. Artificial lenses are implanted at the time of surgery, restoring essentially normal vision. (Without the artificial lens, the dog’s vision will be approximately 20/800, and objects will appear to be reversed, as in a mirror.)
Cataract surgery for dogs is performed routinely with an overall 80 to 90 percent success rate. Long term prognosis following cataract surgery is very good to excellent. Overall, a 95 percent vision rate is reported immediately after cataract surgery, and once cataracts are removed from a dog’s lens, they cannot return.
What Else Could Cause Cloudy Eyes?
During exams, pup parents often raise the concern that a cataract is developing in their dog’s eye. Generally, the vast majority of the time the dog does not have cataracts, but instead has the much more common canine eye condition known as nuclear sclerosis. Nuclear sclerosis in dogs is a normal change that occurs in the lenses of older dogs, and it appears as a slight graying of the lens. The older, denser lens begins to appear cloudy. Nuclear sclerosis in dogs usually occurs in both eyes at the same time and occurs in most dogs who are more than six years old. The condition does not significantly affect vision and treatment is not needed.
Your veterinarian can tell the difference between a cataract and nuclear sclerosis by shining a bright light into the eye. In a dog with a cataract, you are unable to see to the back of the eye (the retina); with nuclear sclerosis, you can still see the retina. Nuclear sclerosis can easily be mistaken for a cataract at first glance, so you’ll want to consult a professional for this one.
If you see cloudiness in one or both of your dog’s eyes, make a trip to the vet. Your veterinarian can perform a complete physical examination, focusing on the eyes, helping to determine the severity of the problem. Next, you can decide the right next steps, considering budget and benefits of treatment. In the end, like everything, it’s a personal decision — and one your dog trusts you to make.
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Dr. Shea Cox, DVM, CVPP, CHPV
Dr. Shea Cox is the founder of BluePearl Pet Hospice and is a global leader in animal hospice and palliative care. With a focus on technology, innovation and education, her efforts are changing the end-of-life landscape in veterinary medicine.