The lens in your eye helps you to see objects clearly both close up and far away. It focuses reflec...
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The lens in your eye helps you to see objects clearly both close up and far away. It focuses reflected light from an object on the retina. The light is converted into nerve signals that are sent to the brain, which translates the signals into vision. Muscles change the curvature and focusing power of the lens according to how far away an object is. As we get older, the lens becomes less flexible and has more trouble curving steeply when we look at something close up. This changes where light is focused on the retina, so close objects may appear blurry. This problem is called presbyopia. Another part of the eye that changes with age is the iris. It consists mostly of muscle, which controls the size of the pupil at its center, and therefore the amount of light that passes through it. As we get older, these muscles become weaker and less able to respond quickly to changes in light, which makes it harder to see in dim light. Eyeglasses help the natural lens to focus images correctly on the retina. Sometimes different lenses are required to correct images from both near and far objects. Contact lenses and permanent lens implants can also be helpful for correcting presbyopia.