Cataracts are a clouding of the eye’s natural lens, which lies behind the iris and the pupil. They can give the appearance of a cloudy or opaque area in the normally clear lens of the eye. The lens is located inside the eye behind the iris, which is the colored part of the eye. It is what our eyes use to focus light on the retina, which in turn sends the image through the optic nerve to the brain. However, if a cataract clouds the lens, light is scattered so the lens can no longer focus properly, causing vision problems. As the condition progresses, the clouded lens allows less light to pass through your eye, and your vision becomes blurred.