In veterinary practice, nuclear sclerosis is a consistent finding in dogs greater than six years old.[4] Nuclear sclerosis appears as a bilateral bluish-grey haziness at the nucleus, or center of the lens, caused by an increase in the refractive index of that part of the lens due to its increased density. It is often confused with cataracts. The condition is differentiated from a cataract by its appearance and by shining a penlight into the eye.