Cataracts in Dogs

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Is Fluffy bumping into things? Tripping over curbs or missing stairs? Is she not recognizing familiar people or objects? Does it feel like she needs reading glasses? If so, it might be time for a trip to the vet and have him check her eyes.

As dogs age, a natural bluish-grey cloudiness develops in the lens of the eye called Nuclear Sclerosis. This is normal and caused by a hardening of the lens. It does not interfere with their distance sight but does affect their ability to focus on objects close up.

Cataracts in dogs, on the other hand, are not a common problem although the incidence of them is on the rise. Some conditions such as diabetes mellitus will increase the likelihood of them developing and certain breeds such as the Miniature Schnauzer, Cocker Spaniel, Siberian Husky, and Labrador and Golden Retrievers are more prone to cataracts. Other causes are trauma to the eye, inflammation and milk replacer so cataracts are often seen in orphaned puppies that were bottle fed.

A cataract is a white opacity within the lens of the eye and greatly effects both distance and up close vision. Although a cataract looks like a film on the surface of the eye, they actually develop deep in the lens that sits behind the iris and pupil. A cataract is caused by an imbalance in the nutrients in the eye (normal levels are 33% protein to 66% water). More water is allowed into the lens and the percentage of insoluble protein increases which forms the cloudiness and adversely affects the transparency of the lens.

Sometimes the cataract will remain small (incipient cataract). This is common in retrievers and they are not always surgically removed. More often, however, the cloudiness continues to grow into immature cataracts which partially block vision before causing full blindness as mature cataracts.

How, when and why a cataract develops is important in developing a treatment plan. Congenital cataracts mean the dog was born with them and although it is most often due to a hereditary condition, they can develop while still in the uterus due to toxins or infection. Developmental or Early Onset Cataracts develop from hereditary traits but can also be caused by diabetes mellitus or trauma as well as infection or toxins. Senile Cataracts occur in dogs over six years of age and are a later-life problem caused from increasing years.

If a dog has either Congenital or Development Cataracts, they should be taken out of a breeding program and spayed or neutered immediately (all breeding stock should pass a Canine Eye Registry Foundation test by an ophthalmologist before being bred so that any possible congenital conditions are caught before they can be passed on).

The earlier cataracts are diagnosed and treated, the greater the chance of restoring much of the original eyesight although the dog will never see as well as it did as a youngster.

Treating Cataracts in Dogs

Conventional treatment usually consists of surgery to remove the cataract from the lens. Left alone, the cataract will eventually lead to an inflammatory condition called Lens Induced Uveitis, or LIU. Anti-inflammatory drops are necessary for the remainder of the dog’s life to prevent conditions such as a detached retina or glaucoma – a condition where pressure increases within the eye often leading to blindness and eventual removal of the eye. LUI decreases the chance of success of cataract surgery hence why early treatment is recommended.

Although there is always a risk, the success rate of cataract surgery for dogs is extremely high with proper postoperative care. For several weeks prior to surgery and for up to six weeks post-op, eye drops must be administered several times a day as well as multiple regular check ups with your veterinarian or the ophthalmologist that performed the surgery.

The most common procedure is called phacoemulsification. It consists of making a small incision and inserting a fine ultrasonic vibrating probe that breaks up the cataract to make removal easier. This is the same surgery that is performed on human cataracts. Less common is extracapsular cataract extraction which involves removing the lens entirely. A new lens is then fitted to allow the dog to focus better – without the artificial lens, the dog will be farsighted with his best range between three and fifteen feet.

Over the last two decades, medical testing in Russia and China has found N-acetylcarnosine to be an effective and physiologically acceptable drug to treat senile cataracts. Not tested by the FDA as of yet, the drug can be bought in the US and is safe for human use as well as on canines. Most users have between an 80 – 90% improvement in the density of the cataract and although it does not replace surgery altogether, it soon will be an acceptable alternative in cases where surgery is not recommended by a veterinary ophthalmologist.

Although cataracts are frustrating and difficult to treat, a dog can lead a normal life post-operatively even with a decrease in the range of their ability to focus. You may find that you have to be their eyes for them with a ‘careful’ command when around stairs or when jumping over obstacles but how different is this than what you would expect as your dog ages? And a ‘careful’ command is a handy one to teach your dog no matter what the age – you never know when an over exuberant play session can have even a dog with perfect eye sight miss a ledge or a hot cup of coffee!

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