Introduction

The term “cataract” refers to any opacity, regardless of size, of the lens of the eye. Dogs of either gender can develop cataracts for a number of different reasons, although in dogs most cataracts have a genetic component. Cataracts become more common with increasing age, although some can be present at birth (congenital cataracts) or develop early in life (juvenile cataracts). Other causes include nutritional deficiency, elevated blood glucose levels due to diabetes mellitus, exposure to toxins, radiation and blunt or penetrating trauma. All cataracts are essentially caused by some change in the protein composition of the lens of the eye or in the arrangement of the lens fibers. Regardless of the cause of cataracts, the clinical signs in domestic dogs are the same.

Symptoms of Cataracts in Dogs

The chief complaints by owners of dogs with cataracts are cloudy, white-ish or blue-grey pupils (or spots in the pupil) and impaired vision. Cataracts can occur in one eye, as is usually the case when cataracts are caused by injury, or they can occur in both eyes. Cataracts can appear suddenly (owners often report that they happen “over night”), or they can develop slowly over a period of years. The cloudiness of the lens may have a crackled appearance, or it may look like a chip of ice. The cataract may appear as a bluish-grey haze over the entire pupil, or only over a part of it. Cataracts will always affect a dog’s vision. Depending on the severity of the cataract, affected dogs will display a range of vision problems from mild to complete blindness. Some of the signs associated with reduced vision include a high-stepped walk, unsure footing, tripping over or bumping into objects, walking into walls, misjudging distances and not recognizing people. Owners of dogs with cataracts may observe some or all of the following symptoms:

• Cloudy pupils in one or both eyes
• Signs of vision impairment (bumping into walls or other objects, tripping, misjudging distances, not recognizing familiar people)
• Increased intake of water and increased frequency of urination in dogs with diabetes mellitus

If your dog displays any of these symptoms, especially if you notice any cloudiness in your dog’s eyes, it is important to make an appointment with your veterinarian as soon as possible. Cataracts are normally painless, but they can cause inflammation and result in permanent eye damage if left untreated. To date, the only effective treatment for cataracts is surgery. Your veterinarian can help you decide whether surgery is necessary or appropriate and whether anti-inflammatory medication is needed.

Dogs at Increased Risk

Older dogs develop cataracts more often than younger dogs, although dogs of any age are at risk. Dogs suffering from diabetes mellitus also tend to develop cataracts more frequently than other animals. Breeds with the highest prevalence of cataracts include the Smooth Fox Terrier, Havanese, Bichon Frise, Boston Terrier.