12. NUCLEAR SCLEROSIS
Illness: When dogs age, the tissue fibers that make up the lenses in their eyes increase, pushing older, inner fibers together and altering the orientation. Since the lens is contained within a small area, there is little room to expand. This makes the lens less clear and results in a pupil that is cloudy and has a blue-grey-white appearance.
Symptoms: Cloudy appearance of the lens in the eye, difficulty determining distances and range
Who's Affected & Why: Nuclear sclerosis is common among older dogs, beginning at the age of 7.
How to Prevent & Cope: There is no way to treat nuclear sclerosis. The best way to cope with this illness is to take good care of your dog and to keep their environment the same so that they can use their other senses to get around. (petMD)