It can get larger or smaller to regulate the amount of light entering your eye. The inside of your eye is filled with a gel-like fluid. Your retina converts light energy into a nerve impulse that is carried to the brain and then interpreted. Some aging-related eye changes can begin as early as your 30's. Aging eyes produce less tears.
Dry eyes can be quite uncomfortable.
All of the eye structures change with aging. The cornea becomes less sensitive, so injuries may not be noticed. The pupil may also change size slower in response to darkness or bright light. The lens becomes yellowed, less flexible, and slightly cloudy. The eye muscles become less able to fully rotate the eye.