Animal Hospital
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Hours of Operation:

Monday: 8:30 a.m.-7 p.m.
Tuesday: 8:30 a.m.-7 p.m.
Wednesday: 8:30 a.m.-5 p.m.
Thursday: 8:30 a.m.-7 p.m.
Friday: 8:30 a.m.-7 p.m.
Saturday: 8:30 a.m.-2 p.m.
Sunday: Closed

Pets get cataracts too

Just like people, pets can get cataracts. So what is a cataract? Why do they occur in animals? And if your pet develops a cataract what can be done?

A cataract is a medical term used to describe abnormal opacities in the lens of the eye that cause a significant loss in vision in both humans and pets — in some cases total blindness. Cataracts are different from a condition called nuclear sclerosis, which is an age-related condition that causes a scarring of the lens and an overall grayish appearance of the lens. In humans, nuclear sclerosis can cause some problems with fine focus such as reading but in dogs and cats that fine focus does not occur so there is no effect on vision until the pet is very old.

Cataracts can occur for a variety of reasons. The most commonly known cause of cataracts in dogs is associated with a glandular condition called diabetes mellitus. Known for short as diabetes, it is a condition of uncontrolled blood sugar.

There are two types of diabetes in veterinary medicine: 1) type I diabetes is a lack of insulin, or the hormone produced by the pancreas that controls blood sugar levels; or 2) type 2 diabetes mellitus where adequate insulin is produced but the body develops resistance — this is associated more with obese cats — and does not use the insulin properly. Either type produces a prolonged hyperglycemia, or high blood sugar scenario.

How does this affect the lens? The lens has no blood supply and relies on diffusion of glucose (blood sugar) from the fluid surrounding the lens for its nutrition. In a patient with normal blood sugar, metabolism of glucose takes place within the lens and then the waste products diffuse back out. However, in a patient with persistently high blood sugar the metabolism pathway is overwhelmed and much of the glucose is converted into two other sugars: fructose and sorbitol, which cannot diffuse out and remain in the lens causing an opacity — or cataract. These cases are usually patients that are not well controlled on injectable insulin.

Unfortunately, even if the patient becomes well controlled after the cataract has developed the process does not reverse itself. Diabetes-induced cataracts in cats is rare. The exact reason why diabetic cats rarely develop cataracts is not known.

Other causes of cataracts are congenital. Congenital refers to hereditary or genetic causes of cataracts. In cats, congenital cataracts is rare. In dogs, it is associated more often with smaller breeds such as the poodle, Cavalier King Charles spaniel, Maltese, shih tzu, bichon frise, Boston terrier and others. It has also been found in both the Labrador and golden retriever but not as common in other large or giant breeds. Trauma and inflammation of the anterior chamber of the eye are the most common causes of cataracts in cats.

Once a cataract develops, staging of the cataract by your veterinarian is imperative. An immature cataract (this refers to opacities at the periphery of the lens) is treated much differently than a mature (complete opacity) cataract. Immature cataracts in a patient that is not diabetic may never progress or progress very slowly. In these cases surgery is not required. However, if a cataract progresses quickly or has already progressed, surgery is recommended immediately.

If a cataract requires surgery your veterinarian will refer you to a board-certified veterinary ophthalmologist. The ophthalmologist will usually require some testing before surgery to make sure that vision behind the lens — specifically retinal function — is intact. The goal of cataract surgery is to restore vision and if there are problems with other portions of the eye then surgery may not be advised. Basically, surgery is the same for pets as for humans: removal of the diseased lens and replacement with a prosthetic lens.

There are many more options for our pets with cataracts if caught early enough. Remember to bring any changes to your veterinarian's attention and schedule routine follow-up appointments for monitoring as recommended. Let's keep our guys seeing straight!

Dr. Kearns has been in practice for 13 years and is pictured with his son Matthew, as well as the newest member of the family, Jasmine, a Labrador retriever.

Matthew Kearns, DVM