What is a Cataract?
A cataract is a clouding of the lens inside the eye and is the most common cause of blindness in dogs. Cataracts can be caused by injuries or diabetes, but most cataracts in dogs are inherited. Any opacity in the lens is called a cataract; very small spots do not significantly affect vision. However, most cataracts will progress, and ultimately cause blindness. The lens is located behind the colored iris; thus when a cataract occurs, the pupil may appear white. Vision through a mature cataract is like looking through white painted glass.
How are Cataracts treated?
There are no medications which are effective in treating or preventing cataracts. A cataract is not a growth; treatment requires surgical removal of the lens and, once removed, a cataract cannot recur. Cataracts are not treated with lasers; the surgery to remove the lens uses phacoemulsification, the same procedure used in people. Once the lens is removed, it is replaced with an artificial lens inserted into the pocket formed by the original lens capsule which remains in the eye. Occasionally, there is a weakness in this capsule which is detected during the cataract surgery. In these cases, sutures may be used to support the artificial lens. If replacement of the lens is not possible, the cataract will still be removed, with resulting vision which is somewhat blurry but significantly better than before surgery. One or both eyes may be candidates for cataract surgery; the doctor will discuss these options with you. We also have a videotape which further explains cataract surgery.
How effective is Cataract Surgery?
Cataract surgery is approximately 90-95% successful. However, this means that in 5-10% of cases, complications may prevent vision recovery. The purpose of the examinations before and after cataract surgery is to detect and prevent these complications whenever possible. In uncomplicated cases, vision will begin to improve within a few days; after six weeks, healing is usually complete and medication is discontinued.
Preparing for Cataract Surgery
Once the doctor has examined your pet and cataract surgery has been agreed upon, a blood analysis will be done to detect any generalized illness and thus minimize the inherent risks associated with general anesthesia. Eye drops will be dispensed to be started before the cataract surgery. You will use these medications after the cataract surgery as well. Your pet will be admitted to the hospital on the morning of the cataract surgery. The hair will be clipped from the area around the eyes and the front legs (to administer the anesthetic). An electro-retinogram test may be necessary to evaluate the function of the retina.
After Cataract Surgery
The cataract surgery takes approximately one hour per eye. Your pet will be monitored in the hospital for several hours after cataract surgery. Although overnight hospitalization is not required, he will need to come back for the first re-examination the day after cataract surgery. When your pet goes home, he will be wearing a large plastic collar to prevent him from rubbing at the eyes. Although he may not like it, he will learn to tolerate the collar and can eat and sleep with it on. It is essential to avoid injury to the eyes after this delicate surgery. Please keep your pet away from other animals during these first two weeks. No bathing or strenuous exercise. Following cataract surgery (in people as well as dogs) there is no significant discomfort, thus pain medication is not necessary. Additional re-examinations will be scheduled at 1, 2, 4, and 6 weeks after the cataract surgery and additionally as needed.
Here is a movie explaining more about cataract surgery for your pet. Double click on cataract movie to begin.
Click here for more information on cataract surgery and what is involved.