What is nuclear sclerosis?

Updated April 17, 2017

Nuclear sclerosis is a condition of the eyes which affects many animals and some humans. It is a hardening and sometimes discolouration of the lens of the eye. As you get older the lens of your eye becomes less flexible. The eye focuses by changing the thickness of the lens. For closer vision, the lens is thickened. Nuclear sclerosis makes this more difficult.


Sclerosis is defined as a hardening of tissue. Nuclear sclerosis is caused when your eye produces new lens fibres. The old ones remain in place and, therefore, the eye becomes more dense. As the lens becomes more dense, it becomes harder and less flexible.


The most common sufferers of nuclear sclerosis are older dogs. Although quite rare, it can occur in humans, and may not appear until a person is at least 45 years of age.


The most common symptom of the condition is that the eyes of the patient, albeit human or canine, begin to become cloudy. This occurs as you become older. In humans, it is seldom noticed before the mid-forties and in dogs not until they are at least seven years old.


Although nuclear sclerosis is seldom seen in humans, it can present as a cloudiness in the eyes. It is sometimes mistaken for cataracts. In general, it does not effect distance vision. Like most people over 45 years of age, nuclear sclerosis sufferers will notice they may need reading glasses to improve their close vision.


Nuclear sclerosis is very common in older dogs. Cloudiness begins to form in the centre of the lens and presents itself in both eyes. This is a natural occurrence in the eyes of older dogs. Distance vision does not seem to be impaired, but the dog's perception of objects that are very close is affected. Cataracts can be mistaken for nuclear sclerosis. Cataracts are a more serious condition and, therefore, you should take your dog to the vet for a checkup if and when cloudiness develops in the eyes.


Veterinaries do not treat nuclear sclerosis in dogs; they view it as simply part of the ageing process. In humans, getting some reading glasses will solve the problem. Nonetheless, talk to your doctor if you think you may have this condition.

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About the Author

Les Belzer has been a professor, entrepreneur, farm owner and writer since 1968. He has written in-house articles on education, mathematics and Spanish literature. Since 1999 he has written travel articles for Escapeartist and "International Living." Belzer holds a Bachelor of Arts in Spanish literature from Idaho State University and a Master of Science in math from the Universidad Mayor de San Simon.