Commonly misconceived as a film growing over the eye, a cataract is actually a cloudiness that forms in the lens. The cloudiness stops a lot of the light entering the eye from passing through to the retina and so reducing the clarity of vision. Cataracts can form as part of the ageing process with increased exposure to UV light so it is very important to wear a good pair of sunglasses and a brimmed hat whenever outdoors to slow down the progression of cataracts. It can also be caused through trauma and certain diseases.
Just like ageing, cataracts cannot be reversed but fortunately, cataracts can be removed surgically and cataract surgery is the most common operation performed in the world today. It is most commonly performed under local anesthesia and normally does not require overnight stay at the hospital/clinic. Improvement in vision can often be noticed after just one or two days but generally takes up to two to three weeks for the eye to recover fully after which new glasses may need to be prescribed.
There is no sure way to prevent cataracts but long-term exposure to UV (ultraviolet) light is believed to induce them. Wearing sunglasses and a wide-brimmed hat in sunlight will decrease your exposure to UV light.