ASK THE VET

Dog’s eye condition might not be caused by cataracts

4/7/2013

Dear Dr. Thompson: I have an 11-year-old dog that seems to be developing what I assume are cataracts in her eyes. Do they have cataract surgery for dogs and will this solve her problem?

The first step would be to determine whether or not she has true cataracts. Cataracts are abnormal changes in the lens of the eye that need to be differentiated from an aging change called lenticular sclerosis.

Lenticular sclerosis refers to hardening of the lens that develops as dogs age. A normal lens has some flexibility that allows for focusing on objects up close and at a distance. When the lens hardens it will not change shape and far-sightedness can develop. This is why I have to hold my morning newspaper a little farther out every year.

Many older dogs can have some loss of vision up close and trouble in low-light conditions, but this is a normal aging change and no treatment is generally needed.

True cataracts are abnormal changes in the lens. They can be genetic in certain breeds or develop with age. The most common developmental cause is diabetes from high blood sugar levels. If a cataract is immature, or just affecting a small portion of the lens, many times your veterinarian will recommend watching the cataract for progression. Cataracts that affect a larger portion of the lens can lead to problems if the lens were to shrivel and start to leak the contents.

The lens material is highly inflammatory to the eye and that inflammation can eventually cause glaucoma, or elevated pressure inside the eye.

Untreated glaucoma will result in vision loss and pain, and may eventually cause her to lose the eye.

Your veterinarian will look at the lens to determine if it is a normal aging change or a cataract. The hardening of a lens has a characteristic appearance when the eye is examined with the pupil slightly dilated. Depending on the extent of the cataracts, some blood tests may be needed to eliminate diabetes as the cause. If she is a candidate for cataract surgery a trip to a veterinary ophthalmologist will be needed.

Surgical correction involves removing the damaged lens and placing an implant. The procedure is similar to those performed on people and once she has healed her vision would be near normal.

However, if the capsule covering the lens is damaged and leaking contents she would not be a good candidate for the procedure, so I would recommend having her evaluated relatively soon.

Questions for Dr. Gary Thompson can be emailed to askthevet@theblade.com or mailed to The Blade, Attn. Ask the Vet, 541 N. Superior St., Toledo, OH 43660. Dr. Thompson regrets that he cannot answer individual letters.