A Close Look at Cataract

I  looked at Zizou fondly, remembering the time he would come bounding in as a puppy. Zizou was now 12 years old, and the familiar cloudiness of his eyes was becoming increasingly visible. I shone a torch on his eyes and confirmed my suspicion. “Zizou has cataracts in both eyes,” I told his guardians. Fortunately, it is not mature yet, and we will keep a watch on it at regular intervals. I sent them home with instructions on what to look out for (bumping into things, scared of going out at night, etc) and called them back for a checkup 3 months later. Fortunately for Zizou, he lived another three years without the cataract maturing too much, and we were able to avoid a surgery. That’s the thing with cataracts in dogs. It is important to diagnose and stage it correctly in order to make decisions about conservative v/s surgical approach.

What exactly is a cataract? Just like us, dogs have a lens in their eyes which is used to focus on objects that they see. In front of this lens is the iris (which gives the eyes a distinctive colour) which expands (dilates) and contracts to allow light in. With age, the lens starts becoming cloudy due to degenerative changes called cataract. Cataracts are classified into four stages: incipient, immature, mature and hyper mature. If only a small portion of the lens is cloudy, it is called an incipient cataract and doesn’t interfere with vision. If it involves a larger portion of the lens, causing blurred vision, it is called immature cataract. If the entire lens is cloudy, it is called a mature cataract. Further changes involve the lens becoming hard and shrivelled (like a grape becoming a raisin). It takes months or years for a cataract to become hyper mature. The loss of water and protein from the lens causes it to shrivel up and form a Mercedes Benz like symbol in the lens (when we see that we joke about the expensive logo, because the patient usually needs surgery).

There are several causes of cataracts, including diabetes, infection, nutritional, and age related degeneration. Treatment usually is unrewarding in terms of reversing the cataract, and surgery is the only option for a cure. In some cases, however, antioxidants in the form of nutritional supplements do help mature cataracts from becoming hyper mature.

Not all dogs that have cataracts need to have surgery, and it is important to work with your vet in coming to this decision. The most important thing you, as a pet parent, will have to assess is vision and quality of life. A lot of dogs are able to compensate very well with blurred vision and move around comfortably in familiar surroundings. In such cases, if there are no complications, and the cataract is not mature, it is better to take the wait- and-watch approach. However, when the cataract becomes hyper mature, complications can set in, including lens-induced inflammation (called lens- induced uveitis) which can, in turn, cause glaucoma, retinal detachment, and/or lens luxation (slippage of the lens from its attachments, allowing the lens to float around inside the eye and cause damage and pain). In these cases, surgery is indicated. Cataract surgery is done either by the conventional method or by phaco emulsification, in which a special probe ultrasonically emulsifies and removes the cataract (all of the lens contents inside the capsule). After the cloudy lens is removed, the empty lens capsule remains and is called the capsular bag. An artificial replacement lens, called an intraocular lens or IOL is placed in the bag. This lens implant is optional, it allows fine focusing and improves quality of vision, but is not mandatory since pets can be comfortable moving around even without an artificial lens implanted.

Cataract surgery is expensive because it requires specialised equipment and training. The instruments and equipment used for cataract surgery in dogs are the same type used for cataract surgery in humans.

In some cases, complications may occur and these need to be discussed with the surgeon before surgery so you know what to expect. Most dogs, however, get tremendous improvement in vision, making the surgery rewarding, since they can see their favourite “humans” and move around comfortably.

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