The lens of the eye plays an important role in vision by focusing incoming light on the retina, the part of the eye responsible for processing images into nerve signals and sending them to the brain through the optic nerve. While the lens is clear and flexible when you are young, aging can affect function and clarity, making it more difficult to see clearly.
Identification
The lens is located behind the pupil, the dark opening in the center of the colored iris. The lens, also called the crystalline lens, is a clear, hard disc that helps you focus on objects. The lens can change shape to allow for near and far vision. The KidsHealth website reports that when you look at things at a close distance, the lens become thicker to focus the correct image on the retina. The lens becomes thinner when you look at objects at a distance.
The Role of the Ciliary Muscles
The ciliary muscles connect the lens to the eye. The ciliary muscles change the shape of the lens by pulling or loosening the zonule fibers located inside the ciliary muscles, according to the University of Alabama at Birmingham. When the zonule fibers increase or decrease pressure on the lens, the shape changes.
Considerations
The cornea, lens and retina work together to provide clear images to your brain. In order to see clearly, both the lens and the cornea must have a perfectly smooth curvature like the surface of a rubber ball, according to MayoClinic.com. The cornea is the clear tissue that covers the front of your eye. If your cornea isn't curved evenly or if the shape of your eyeball is too long or short, it will be impossible for your lens to focus light rays on your retina correctly and you might experience blurred vision. Blurred vision might be corrected by wearing prescription eyeglasses or contact lenses, or undergoing laser surgery to modify the shape of your cornea.
Aging and the Lens
As you age, the lens and the ciliary muscles becomes less flexible. Because the lens can no longer change shape quite as easily, it might be difficult to clearly see close objects, even if you already wear glasses or contacts. This condition, called presbyopia, usually occurs beginning around age 40, according to the All About Vision website. Wearing bifocal or progressive lenses or undergoing laser surgery can help you see more clearly at all distances if you develop presbyopia.
Cataract
Aging also can cause a cataract, or clouding of the lens. The National Eye Institute reports that by age 80, more than half of all American either have a cataract or have had cataract surgery. If a cataract significantly interferes with your vision, your doctor can perform surgery to remove the cloudy lens and replace it with a plastic lens.
