If you're in your mid-fifties or older, there's a good chance that your eyes have started to develop cataracts. You can't see them, you can't feel them, and until they begin to seriously affect your vision you don't really need to do anything about them except continue to take good care of your eyes. That means having regular eye exams and protecting your eyes-from injury, from the sun's ultraviolet (UV) rays, and from irritants such as dust and wind.

A cataract is a clouding of the natural lens inside the eye. The clouded areas are often called opacities because they are opaque, meaning they are not clear, and light cannot pass through. The lens must be crystal clear to do its focusing job, so the areas of opacity interfere with good vision.