Have you noticed that the pupils of your dog’s eyes are getting grey and even slightly white as it ages? Are you scared it is cataracts and she is going blind? Cataracts do occur in dogs and it does result in total blindness. However there is a more common geriatric change in the eyes called lenticular sclerosis. So what are these changes in the eyes of a dog?
Although common, most dogs do not develop geriatric cataracts. Most of the cataracts we see in veterinary practice are in dogs that suffer from diabetes. All diabetic dogs will develop cataracts, sometimes within only 6 months after the diagnosis of their disease. It will occur even in dogs that are well regulated with their insulin dose. Dogs with cataracts, whether geriatric or diabetic, are blind. Dogs adapt readily to the blindness and easily move around their known environment. Moving the furniture or other changes may cause temporary setbacks.
The vision in dogs with cataracts can be restored with removal of the lens. The procedure must be performed by a board certified veterinary ophthalmologist and is presently quite pricey. But more likely your senior pet has a condition that is very similar to our need for reading glasses as we age. This condition will not cause blindness.
This condition is called lenticular or nuclear sclerosis. The grey to chalky color change is the aging of the lenses in your dog’s eyes. The lens of the eye is tethered by muscles behind the pupil and iris or colored part of the eye. The muscles stretch or squeeze the gel filled lens to adjust its shape and focus light and images coming through the pupil.
As dog’s age the gel inside the lens becomes thicker, hardened and changes color. The graying of the lens starts at about 5 years of age and becomes more chalky or milky looking as the years pass. We veterinarians use the color to estimate the age in our older patients that don’t have birthdate information.
Dogs continue to see through this lens change. The images may not be as sharp but the dogs are not blind. In dim light or dark they may see better because the pupil is larger and allows more light to pass through the lens.
In very old dogs the capsule of the lens can start to leak. This gel is recognized as foreign to the immune system and is attacked by white blood cells as if it were bacteria or a virus. This inflammation causes the white of the eyeball, the sclera to become irritated and red. Your vet can provide eye medication to reduce the discomfort of this condition.
Prevention of Lenticular Sclerosis
Unfortunately, lenticular sclerosis cannot be prevented. However a well-balanced diet and healthy lifestyle can slow the aging process and perhaps delay the onset of this condition.