Cataracts are quite common in dogs. According to the American College of Veterinary Ophthalmologists, cataracts affect about 97 breeds. The breeds with the highest cataract prevalence include the Smooth Fox Terrier, Havanese, Bichon Frise, Boston Terrier, Miniature Poodle, Silky Terrier, Toy Poodle, American Cocker Spaniel, Standard Poodle, and Miniature Schnauzer. Congenital cataracts may or may not be inherited and generally do not progress to blindness, although in puppyhood such a cataract may represent a visual handicap. They are readily amenable to surgical intervention, with excellent results in terms of restoration of vision and replacement of the damaged lens with a synthetic one. Potential breeding stock should be evaluated by the Canine Eye Registration Foundation (CERF). A CERF examination will detect hereditary eye problems, such as cataracts and progressive retinal atrophy.
A normal lens, which sits behind the pupil, is transparent and focuses light onto the retina. The retina sends the image to the brain, where vision is perceived. When the cells and the protein of the lens begin to deteriorate, a cataract forms. The lens gets cloudy and the light cannot be transmitted to the retina. Although most cataracts in dogs are inherited, less commonly they can result from trauma or other eye diseases, including uveitis, glaucoma, lens luxation, and retinal degeneration. Underlying systemic metabolic diseases including diabetes and Cushing disease, have also been implicated in the formation of cataracts.
Cataracts are quite common in older dogs. The slight haziness that appears in an older dog's pupils is normal and has minimal effect upon vision. It is when the cataract becomes severe that you'll notice the dog losing all sight. Some people call any cloudiness of the lens in old dogs a senile cataract, when in reality it is a condition called nuclear sclerosis. Nuclear sclerosis occurs when, over time, the fibers of the lens become more dense and light is reflected off the back of the lens capsule. This gives the lens a cloudy appearance, which looks very much like a cataract, but it is not. These dogs learn to watch for blurred, unfocused movement and rely more on smell, sounds and vibrations for their sensory input. Dogs with cataracts generally do very well until the last stages of opaqueness. Even though they can't distinguish sharp edges and small shapes, they can follow general movements and actually compensate very well.
Cataracts are treated using phacoemulsification surgical procedure that involves usings high-frequency sound-waves to destroy the lens. After the lens has been destroyed, a suction device then removes the lens particles from the eye, and an intraocular lens implant (artificial lens) is inserted. Surgery takes one hour per eye with the success rate exceeding 90%. However, in dogs diagnosed with progressive retinal atrophy cataract surgery cannot restore vision, because the retina has become nonfunctional.
- Marsili V, Calzuola I, Gianfranceschi GL. Nutritional relevance of wheat sprouts containing high levels of organic phosphates and antioxidant compounds
- Dr. Carol Osborne. Dr. Carol's Naturally Healthy Dogs