By Dr. Karen Shaw Becker
Both dogs and cats can develop cataracts, but they're much more common in dogs. Cataracts in pets can progress very slowly over many years or they can come on very quickly, leading to blindness within a few days or weeks.
Types of Cataracts
The lens of the eye is inside a clear capsule, and cataracts cloud up the inside of the capsule. So a cataract in your pet's eye is technically a change inside the clear capsule that contains the lens, not a film over the eye itself.
- An incipient cataract means the clouding of the lens is still minor and may not even interfere with your pet's vision.
- An immature cataract means that there's a greater portion of the lens that is clouded and probably some blurred vision.
- Cataracts are considered mature when the entire lens is clouded and most or all of your pet's vision is lost.
- There are also hyper-mature cataracts. These develop over months or years and cause the lens capsule to wrinkle and the lens inside to shrivel up. Some hyper-mature cataracts are completely cloudy. Others have clear areas that allow some vision if the rest of the eye is still functional.
Even with progressive cataracts, your pet may still be able to see some things. But as the cataracts progress, the pupil, which is the black dot in the center of your pet's eye, can go from black to a bluish color, and even to white.
Thankfully, cataracts are rare in kitties and are usually caused by an eye infection or injury. Uveitis is a common inflammatory eye condition that is often a suspected underlying cause of cataract formation in cats. Uveitis is a painful condition that causes kitties to squint, have watery eyes, sensitivity to light and even spasms of the eyelids.
Chronic uveitis is often secondary to significant infectious diseases like feline leukemia virus (FeLV), feline immunodeficiency virus (FIV), feline infectious peritonitis (FIP) and toxoplasmosis. Hereditary feline cataracts are extremely rare. Cats can develop diabetic cataracts, but this too is quite uncommon.
Cataracts in dogs are much more common and more clinically significant than in cats. Many dogs are genetically predisposed to cataracts, and they can develop at any age. The condition is more prevalent in certain breeds, including the Cocker Spaniel, Poodle, Siberian Husky, Schnauzer, Old English Sheepdog, Samoyed, Golden and Labrador Retrievers, Maltese, Boston Terrier and the Yorkshire Terrier.
Diabetes is a primary cause of cataracts in dogs. Certainly in my experience, the majority of cataracts I see are the result of diabetes. Estimates are that 75 percent of diabetic dogs will develop blindness from cataracts within a year of diagnosis, which is why I recommend beginning eye support the minute your dog is diagnosed with diabetes.
Diabetic cataracts can occur very quickly — sometimes literally overnight. Your dog goes to bed with normal eyes, and wakes up in the morning with white pupils, which can be scary. If this sudden change occurs in your pet's eyes, you should get him to the veterinarian right away for a diabetes workup.
If the diabetes is well-controlled and so is the inflammation associated with the cataract, these dogs can be good candidates for cataract surgery, which I'll discuss in a minute.
Cataracts in dogs can also be secondary to another underlying eye condition such as progressive retinal atrophy, uveitis or glaucoma. If your dog is diagnosed with cataracts, it's important that your vet makes sure there's not another underlying eye disorder as well. Another common cause of cataracts in dogs is toxicity from drugs like vaccines, heartworm preventives and flea/tick medications.
Trauma to a dog's eye can cause the lens capsule to rupture. In a rupture, the contents of the lens leak out. This can lead to a severe form of uveitis, which can then lead to secondary cataracts. If your dog suffers any type of injury to the eye, it's important you go to the veterinarian as soon as possible. Sometimes you can't tell right away if there's damage to the lens capsule, and by the time it's noticeable it can be too late to save your pet's vision.
Puppies fed a nutritionally unbalanced milk replacement can develop cataracts due to nutritional deficiencies. Fortunately, this type of cataract often improves as the puppy grows older.
Older dogs can develop cataracts secondary to the aging process, but these are usually small, very slow to develop and don't cause serious vision problems. Again, the minute you see changes in your senior dog's eyes, begin a proactive, preventive protocol to slow down the progression of the disorder.
If you suspect your pet has a cataract because you see some clouding of the eye or she seems to be having vision problems, I recommend a visit to your veterinarian, or even better, an appointment with a veterinary ophthalmologist for a complete eye examination.
If the diagnosis is cataracts, less troublesome ones will be rechecked periodically to see if they're progressing. Sometimes anti-inflammatory eye drops are prescribed, and I also prescribe antioxidants that can specifically cross the blood-brain barrier to support remaining ocular function and health. If your pet's vision is affected, her quality of life is compromised. If the cataracts are progressing rapidly, surgery is sometimes recommended to restore vision.
Veterinary Cataract Surgery
If a veterinary ophthalmologist recommends cataract surgery for your pet, the outcome will be better if you do it sooner rather than later — preferably before the cataract matures. Mature cataracts are much more difficult to manage during surgery than less advanced cataracts.
The procedure to remove cataracts is done under general anesthesia. A very small incision is made in the eye, and most often a procedure called phacoemulsification, which is the same technique used on human cataracts, is used to break down the cataract and remove the cloudy lens.
Once the lens is removed from the lens capsule, most pets receive a replacement implant. The implant is permanent, just like in people, and can restore almost normal vision to your pet. In some cases, completely normal vision is achieved.
Successful cataract surgery results in an immediate and profound cure for pets who've been suffering from decreased vision. They wake up from anesthesia and it's a brand new world. It can be a very expensive but incredibly rewarding surgery that restores your pet's vision.
However, sometimes the lens capsule is loose-fitting or can't be fragmented completely by emulsification. When this happens, the lens and lens capsule are removed, and in this situation there's obviously no way to do a lens replacement. Pets with this issue can still see after their surgery — they just won't see as well as animals who've received a replacement lens.
Patients with the whole lens removed will also end up being farsighted, which means objects close to them will be blurry. But there's nothing to worry about, because these pets adjust beautifully and usually wind up with good functional vision over time.
How to Help Prevent Degenerative Eye Disease in Your Pet
There are things you can do to help reduce or prevent cataract formation in your pet, one of the most important of which is to keep her at a normal weight and feed a species-appropriate diet so she doesn't develop diabetes. It's a common sense step, but often people don't think about it until it's too late.
Cataracts are inevitable in dogs with uncontrolled diabetes. They are fast-acting and will render your dog blind within a short period of time. Surgery is your only option to restore vision to your pet, and the success of the surgery is often dependent on how well you're able to manage the diabetes.
A far simpler and certainly much kinder and less expensive approach is to keep your dog in excellent physical condition. Feed a biologically appropriate diet, which means low glycemic, grain free, carbohydrate free and low starch. Maintain your pet at a healthy weight.
I also highly recommend that you not allow your pet to be over-vaccinated. Annual revaccinations are unnecessary in most situations. In addition, many of the medications that veterinarians routinely prescribe are unnecessary. Keep all chemicals going into and onto your pet's body at a bare. We know some cataracts develop as a result of drug-related systemic toxicosis.
For dogs at midlife (between about 5 and 7 years of age), adding in some antioxidants and herbs that can specifically help guard against cataract formation is wise, especially if you have a breed that is predisposed. Regular visitors here at Mercola Healthy Pets know that as far as I'm concerned, the best source of antioxidants is real food.
That means serving your pet a nutritionally balanced, fresh food diet. Antioxidants scavenge free radicals and can slow down degenerative changes in your pet's eyes. Specifically, vitamin C and E are antioxidants that are thought to slow down the development and progression of cataracts.
An excellent supplement you can add to your pet's food in pill or raw food form (even as training treats) is bilberries. Bilberries are rich sources of flavonoids and have superior antioxidant properties. Taken with vitamin E, they are known to be protective to the eye tissue in humans, and have proven to halt lens clouding in nearly all people with early stage cataracts. I've seen this to be true in pets as well, if you catch them early enough.
You can also talk with your holistic veterinarian about supplementing your dog's diet with beta-carotene or astaxanthin. I love astaxanthin for the eyes because it crosses the blood-brain barrier and does a wonderful job scavenging free radicals within the eyes. Dogs also benefit from supplemental glutathione and alpha-lipoic acid, which are antioxidants that have been shown to dramatically reduce the risk of developing cataracts and other eye disorders.
There are also nutraceutical eye drops and Chinese herbs that have shown good success in reducing how quickly lens degeneration occurs in pets. Those products can be prescribed by your holistic veterinarian based on your pet's specific eye changes. Most importantly, if you see changes occurring in your pet's eyes, have your dog or cat evaluated by your veterinarian to make sure you're doing all you can to prevent further degeneration, and to slow or even stop the progression of an existing condition like cataracts.