Aging of an eye lens
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What Is Nuclear Sclerosis?

April 23, 2013

Nuclear sclerosis is the cloudiness of the eye lens that affects many animals and some humans. Animals like cats, dogs and horses are all affected by this eye condition. It is a result of aging process of the lens. The nucleus, which is the central part of the lens gets dense and looks like a grey haze inside the eye. In a vet practice, it is also referred to as lenticular sclerosis or old eye.

nuclear sclerosis in dogHow is it formed?

New lens fibers are formed in the periphery of the lens throughout the life. But as the lens ages, the newly formed fibers push the outermost portion of the old fibers inwards, thus causing the inner portion of the lens to become cloudy and denser. However, unlike cataract, in this condition the normal arrangements of lens fibers are not affected or disrupted thus do not have any impact on the vision. In humans, cloudiness of the lens may result in presbyopia, which means the ability of the lens to accommodate is lost completely. Accommodation is nothing but a mechanism by which the eye focuses on objects that are close to it. It is very important for an eye to accommodate in order to read or watch TV effectively. It has been understood that, it is this eye condition that makes most people at about 45 years of age to require reading glasses.

Symptoms of nuclear sclerosis

The most common symptoms of this eye condition is that the eyes of the person affected, human or animal starts to become cloudy. It usually happens when a person or canine becomes older. Generally, nuclear sclerosis is not noticed in human beings before they reach their forties and in dogs not until they reach 7 years old.

Compared to animals, this eye disease is found rarely in humans. Affected individual shows cloudiness in their eyes and are often mistaken as cataract formation. However, it does have an effect only on the near sight, which can be easily corrected using eye glasses.

Cloudiness of the lens is also common in dogs especially that are at least 7 years old. It normally begins in the center of the lens and can be found in both eyes. Like humans, the distant vision of the dogs are normally not affected by old eye, but its perception on objects that are close to it are generally affected. Since, this condition looks similar to cataracts which are a more serious condition, dogs should be taken to the vet for a check-up if cloudiness appears.

Cloudiness of the lens can also affect cats and other animals, the same way it affects dogs. In cats, it normally begins to develop when they are at least 8 years old.


Nuclear sclerosis is an effect of the normal aging process. In animals, veterinarians diagnose this condition using a simple eye check-up. Pupil dilation can help identify them whether the animal suffers from this condition or not.

To diagnose lenticular sclerosis, the vet will shine a penlight on to the dog’s eyes. Dogs that suffer from cataract do not reflect light, but dogs that have old eye problem will have a reflection of the penlight in their eyes.

It is an eye condition that does not cause any pain to the sufferer as well as clinically not affect the vision in most animals. So it does not require any treatment. But animals suffering from lens cloudiness should be supervised closely when they are outdoors. To ensure good ocular health, pets should be checked periodically by a vet. This is because, older pets can develop cataracts and if they go undiagnosed it can lead to permanent loss of vision.

Humans affected with lens cloudiness are treated by prescribing proper reading glasses, which may solve the problem


Many changes occur when humans and animals begin to enter old age. One of them is the old eye, which is a condition that causes cloudiness of the eye lens. This condition does not clinically affect the vision of the sufferer, however it can create trouble viewing near objects clearly. It requires no medical treatment, and eye glasses are prescribed to humans to continue with their normal activities. Also, there are no ways to prevent nuclear sclerosis from occurring because it can happen to anyone as they age.