The eye works much like a camera, and like a camera, depends on a clear lens to focus images. A lens with a cataract makes it impossible to see clearly.

When we look at an object, light reflects off the object and enters our eye. The lens focuses this light onto the retina at the back of the eye. The retina then converts these rays into electrical impulses that travel through the optic nerve to the brain. The brain converts the electrical impulses into images, allowing us to "see." Seeing clearly depends in large part on the clarity of the lens through which light passes.

Learn more about how the eye works and how this changes as we age.