Dog CataractLike a camera, eyes have a clear lens inside them that is used for focusing. A cataract is any opacity within a lens. The opacity can be very small (incipient cataract) and not interfere with vision. It can involve more of the lens (immature cataract) and cause blurred vision. Eventually, the entire lens can become cloudy, and all functional vision lost. This is a mature cataract in dog.
The most common cause of a cataract are inherited. Other causes include injuries to the eye or diseases such as diabetes mellitus (“sugar diabetes”). Some appear to occur spontaneously and are age related.
Many breeds of dogs are affected with hereditary cataracts. Some of the recognized breeds include the American Cocker, Labrador, Poodle, and the Boston Terrier to mention a few.
Since the major cause of a dog cataract is hereditary, cataract progression varies from breed to breed. In some breeds cataracts will develop relatively early in life whereas in others the first signs are detected when the dog is older and progression is so slow that dogs still have reasonable sight well into old age.
Once a dog's lens has developed a cataract, there is no known method to make the lens clear again. An immature or mature dog cataract can be treated only by surgically removing it.
The procedures and equipment used to remove a cataract in dog are the same as those used in humans.
A small incision is made in the eye and a hole is made in the capsular bag that holds the lens. Phacoemulsification is then performed, in which a special probe ultrasonically emulsifies and removes the cataract.
After the entire lens is removed, an artificial replacement lens, called an intraocular lens or IOL, is placed in the bag. The eye is closed with extremely small sutures.
Because even the slightest damage to structures in the dog's eye can have disastrous effects, the surgery is performed under high magnification using an operating microscope. If both eyes are affected, usually both eyes are operated on at the same time.
After successful dog cataract surgery most see close to normal. Also after surgery, a cataract cannot recur again.
However, some can have decreased vision years after dog cataract surgery due to formed scar tissue, glaucoma, or retinal detachment.
Obviously, the patient must be in good general health to undergo surgery; if diabetic, diabetics must be well regulated before cataract surgery.
Also, it should be obvious that in order for a patient to be a good candidate for surgery, the patient must have a temperament conducive to the administration of eye drops at home.
Dogs with cataract in one eye, that see good with the other
eye generally do not need dog cataract surgery.
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