Nuclear sclerosis forms as newly formed lens fibers in the eye push old lens fibers inward. It is the result of the aging process of the lens, and it causes the eyes to appear gray and cloudy.
Nuclear sclerosis affects both animals and humans, but it is more commonly found in animals such as cats, dogs and horses. This condition doesn't usually affect eyesight in animals, but may require humans to need reading glasses to correct slight changes in vision. In humans, it can cause presbyopia in rare cases. Due to its lack of symptoms, many veterinarians and animal owners do not treat the problem.