Cloudy Eyes in Dogs

Your dog has gotten cloudy eyes and you are wondering if you should be worried. Isn’t this just one of those changes that comes with getting older? You may be right, dogs’ eyes do indeed get cloudier with age and this age related cloudiness is called nuclear sclerosis. The eyes however, can get cloudy for different reasons, like cataracts (a breakdown of the fibres which make up the lens of the eye). How can you tell the difference? The truth is, is that you can’t tell the difference between nuclear sclerosis and cataracts by just looking at the dog. Nuclear sclerosis is the normal cloudy eye that develops with age. To tell the difference between the two you will have to take your dog to the veterinarian. But first, here is some information about cloudy eyes.

The lens of the eye is a solid disc located in the centre of the eye. It sits right behind the iris (the coloured part) of the eye. You cannot normally see it because it is entirely transparent, like glass. Light travels into the eye, through the pupil, through the lens (which we cannot see), and to the back of the eye (where the nerves sense the light). The lens is an important part of the eye, and when it changes shape it allows us to see at different distances. In order to see far away and up close, the lens needs to be working properly.

As your dog ages, changes occur all over the body. Perhaps it has less energy, gets a little chubbier, or may become a little arthritic. Inside of the eye, changes are also taking place. Throughout your dog’s life, new layers on the outside of the lens are constantly being created. These layers stack up like layers of an onion, around the centre of the lens (the ‘nucleus’ of the lens). All of these layers, including the nucleus, are transparent.

As the dog ages, the nucleus gets harder. It starts to become less transparent, and more ‘cloudy’. This hardening of the lens causes the bluish cloudiness that you may notice in your older dog. The cloudiness is located near the pupil. This process is gradual and does not cause vision problems until your dog is fairly old. This is called nuclear sclerosis.

Cataracts also cause a bluish cloud near the pupil. Cataracts also involve the lens. But cataracts are very different from nuclear sclerosis. They are not normal structures for your average elderly dog. Cataracts are formed when the actual structure of the lens begins to change. The lens can swell, shrink, or even burst. The damaged structure of the lens is no longer transparent, and you will see cloudiness.

Cataracts are more common in older dogs than in younger dogs. This may be because, over time, older dogs have been exposed to more things that can harm their eyes. Cataracts have a wide variety of causes, including radiation (or UV light), injury, malnutrition, genetics, and a large number of diseases like diabetes which increase the risk of cataracts. Cataracts can also cause other eye issues if they are not treated, or if they become complicated.

Don’t worry, cataracts are not an emergency but it is important for you to have your dog evaluated by your veterinarian to determine the cause of the ‘cloudy eyes’. Between you and your veterinarian, you can determine how you would like to treat your dog. Most often, there is no treatment done for nuclear sclerosis, because the dog can adjust amazingly well to a decreased ability to see. Dogs have such great senses that they do very well even if they are blind.

Cataracts have a few options for treatments, and one of them is surgery. Cataract surgery has been performed in humans for many years, and is available for pets as well. It is somewhat expensive, and you will have to bring your dog to an eye specialist (ophthalmologist) in order to get it done. Your decision will depend on the age and health of your dog, how bad the cataract is, and the cost of the surgery.

Cloudy eyes are common findings in old dogs. But there isn’t just one cause for cloudy eyes, and you should make sure that you see your veterinarian to confirm that your dog is just experiencing the normal aging process. Just because your dog has cloudy eyes, doesn’t mean it can’t see and even if it can’t see, doesn’t mean that your dog isn’t happy! Blind dogs adjust well to their environment and function very well. The next time you take your elderly dog to the veterinarian, make sure you discuss its eyes.
By Ashley O’Driscoll – Pets.ca writer