A cataract is any opacity in the lens of the eye. The normal lens is translucent (clear), and it transmits and focuses light onto the retina in the back of the eye. A cataract within the lens may block the transmission of light to the retina.
There are many causes of cataracts. The most common form of cataracts in the dog are genetic, inherited types. For genetic cataracts, the age of onset and severity varies among the various breeds of dogs.
Cataracts may also develop following trauma to the eye, in association with metabolic diseases such as diabetes, from nutritional disorders during puppy hood, or secondary to other eye diseases. Cataracts may develop spontaneously in old age, but should not be confused with nuclear or lenticular sclerosis, an aging change that often occurs in the canine lens and does not cause blindness. Rarely cataracts may develop following exposure to certain drugs, toxins, concentrated microwaves, radiation, or following electrocution.
Cataracts cause varying levels of vision impairment and may lead to blindness.
What to Watch For · Bluish, gray or white color change inside of the eye · Tendency to bump into things · Reluctance to use stairs or jump up onto objects · Hesitancy in unfamiliar environments · Other signs of blindness · Inflammation or redness · Pain and squinting due to the underlying cause
Diagnosis
Diagnostic tests are necessary to recognize cataracts and exclude other diseases. Tests may include: · A complete medical history and physical examination. · A complete eye examination. Most veterinarians have the tools with which to confirm the presence of a cataract in the lens, but it is often necessary to visit a veterinary ophthalmologist to have a more thorough examination performed using an indirect ophthalmoscope and a slit lamp biomicroscope. · Blood tests to determine any underlying causes · An ultrasound examination of the eye if the cataract is too opaque to allow examination of the retina. · Possibly an electroretinogram to evaluate the function of the retina, especially if the cataract blocks visualization of the retina.
Treatment · There is no medical treatment available to reverse cataracts, to prevent cataracts or to shrink cataracts. · Cataracts that are inherited or are not complicated by other eye diseases may be surgically removed. Cataracts associated with other eye diseases, such as inflammation (uveitis) cannot be removed surgically until the inflammation is brought under control. · Whether a dog is a candidate for cataract surgery can be determined by a veterinary ophthalmologist. · Treatment must also be instituted for any underlying causes, such as diabetes, etc.
Home Care and Prevention
It is important to have all dogs with cataracts examined early in the course of their disease to determine whether the cataract is inherited or is secondary to other conditions. It is also important to determine whether the cataract itself is affecting the eye, such as causing inflammation or glaucoma. Early evaluation by a veterinary ophthalmologist allows appropriate therapy to be instituted for ancillary problems and allows a determination to be made as to whether the dog is a candidate for cataract surgery.
If your dog has inoperable cataracts, he may require help in adjusting to his blindness. Be sure to keep objects around the house in a consistent place. Confine the dog to a fenced yard or leash walking. Most blind pets function extremely well in familiar environments.
There is little you can do to prevent cataracts. If your pet is diagnosed with inherited cataracts, notify the breeder so that no other litters are produced from the same sire and dam.
If your dog is diagnosed with diabetes, then monitor blood and urine sugar as recommended by your veterinarian. Maintain good control of the diabetes. |
Cataracts 
