Final answer:
A cataract is the term for the cloudiness of the eye's lens resulting from protein deposits that build up over time, potentially leading to vision loss. Treatment is commonly done by replacing the lens, and protection against UV rays can help prevent cataracts. Presbyopia is another age-related vision issue where the eye loses its ability to focus on close objects, which is corrected with lenses.
Step-by-step explanation:
The cloudiness of the lens due to protein deposits on its surface, which can lead to vision loss, is known as a cataract. Cataracts occur when there is clouding in the lens of the eye, preventing sufficient light from entering, which is essential for vision. Over time, this condition can lead to blindness, especially if left untreated. Factors such as aging, repeated exposure to UV-B rays, and nutritional deficiencies can increase the risk of developing cataracts. However, treatments such as the replacement of the clouded lens with a plastic lens are both easy and successful. It is also important to protect the eyes from UV rays to prevent the formation of cataracts; wearing plastic sunglasses can offer better protection than those made of glass.
Another age-related vision issue is presbyopia, which is a common vision problem where the eye loses its ability to focus on close objects. This is thought to be due to the lens becoming less elastic with age and the muscles controlling the lens weakening. Unlike cataracts, surgical procedures to correct presbyopia are not as successful, so corrective lenses are typically used.
It should be noted that light passing through a cataract is diffused, which further impairs vision. When repairing a tear in the retina with laser light, the rays entering the eye must be parallel to ensure precise application and to prevent further damage to the eye's internal structures.