Your pet's health

Is my dog going blind?

Reader's letter:

"I have noticed that my ten year old Golden Retriever has a blue-grey haze when I look into the centre of his eyes, I am worried that he is getting cataracts and is possibly going blind. If it is cataracts, will he need surgery or is there any other treatment?”

Dear Reader, from your description, although it is quite possible that your dog is developing cataracts, it is also possible that this change in the appearance of his eyes is being caused by another condition. A cataract is an abnormality of the lens within the eye which causes it to become opaque. It can affect one or both eyes. If the cataract is very small, it may not interfere with the dog's vision. If it involves a larger part of the lens, it can cause blurred vision. If it involves the entire lens, all vision will be lost in the affected eye.

Cataracts have many possible causes in dogs, but most are inherited genetically and can occur at any age. Inherited cataracts can be seen at a young age, i.e. from six months old onwards, and are more common in certain breeds, e.g. Cocker Spaniel, Bichon Frise, Poodle, Golden Retriever. Another cause of cataracts is diabetes, where they develop very quickly. They can also develop following an inflammation inside the eye.

It is possible that the change in the appearance of your dog's eyes is caused by a process called nuclear sclerosis of the lens, which is age-related and affects many older dogs, basically involving a hardening of the lens. It is not the same as a cataract, and usually does not significantly affect sight, unless it occurs together with cataracts.

In short, it would be impossible to diagnose the cause of your dog's abnormality without a proper veterinary examination. During a routine veterinary consultation, a simple and painless exam of your dog's eyes will differentiate between these two conditions, or any other possible cause of the problem, e.g. inflammation of the cornea, the normally transparent layer on the surface of the eyeball.

As regards treatment of cataracts, once they have developed, they can only be treated by surgical removal. It is a highly specialised and delicate procedure which is carried out by an opthalmologist in referral veterinary centres. However, not all dogs with cataracts definitely need surgery, as it depends on how large the cataract is and how much it is interfering with vision.