Dog - Cataracts

What is a cataract?

Inside the eye the lens helps to focus light entering the eye through the pupil on to the retina, the light-sensitive surface at the back of the eye. This is very similar to a camera. Imagine the retina as the film (or light-sensitive surface in a digital camera). Normally the lens is transparent. If the whole or part of the lens within the dog’s eye becomes opaque this is called a cataract.

What causes cataracts?

Some cataracts are the result of injury or diseases such as sugar diabetes, (Diabetes mellitus). Some appear to occur spontaneously and are age related. However in the dog by far the largest number of cataracts are inherited.

Are some breeds more prone than others?

Many breeds of dogs are affected with hereditary cataracts. Among these are American Cockers, Labrador and Golden Retrievers, Poodles, Boston Terriers and Staffordshire Bull Terriers. As dogs are living to an older age, senile cataracts are also becoming more prevalent in dogs generally.

Will my dog go blind?

If cataracts occupy less than 30% of the lens or only one lens is affected they will often go unnoticed by the dog. When the opacity is affecting about 60% of the total lens area, vision impairment is usually apparent. If the opacity progresses to 100% of the lens the dog is then unable to see. Whether the cataract remains static or progresses depends on the type of cataract, breed and other factors.

Can anything be done to prevent my dog from going blind?

If the lens is sufficiently opaque to impair vision it can be removed by specialist surgical techniques. Referral to a veterinary ophthalmologist will be necessary for this. Following this operation (lendectomy) the dog has a good chance of seeing again but the outcome cannot be guaranteed.

How old will my dog be if he does go blind?

Since the major cause of cataract is hereditary, cataract progression depends on breed. In some breeds cataracts will develop relatively early in life, and vision can be lost at a young age. In other breeds, the first signs are detected when the dog is several years old. Progression can be very slow so that affected dogs can retain reasonable sight well into old age.

If the condition is hereditary, what can be done to prevent it being passed on?

This is a situation where prevention is better than cure. In the UK, the joint British Veterinary Association/Kennel Club/International Sheepdog Society eye disease certification scheme offers breeders an excellent chance to make sure they are producing puppies from disease free stock. Similar schemes are in operation worldwide. In addition genetic tests are available for some inherited forms of cataract. We will be more than happy to discuss details with you.