Cataracts cause the lens of the eye to become cloudy, often resulting in blurry vision and double vision. Other symptoms of cataracts include poor night vision and frequent prescription changes for eyeglasses or contact lenses. In most cases, the only available treatment for a cataract involves surgery. However, it is a common procedure -- more than 1 million cataract surgeries are performed each year in the United States. It can take years for a cataract to affect vision, and some people with cataracts never need surgery. If you have a cataract, it's important to have your vision tested regularly.