Cataracts are vision problems in which there is a clouding of the lens of the eye. When the lens becomes cloudy, the flow of light is distorted and the picture formed on your retina becomes dim or blurry. While there are several types of cataracts, age-related cataracts are the most common form of the condition. Symptoms of cataracts include blurry vision, poor night vision, and difficulty reading. These symptoms can increase your risk of falls and fractures. A cataract can occur in either or both eyes, but it cannot spread from one eye to the other. In most cases, the only available treatment for cataracts involves surgery. Although research scientists know how the lens of the eye clouds and that certain things can raise a person's risk of developing cataracts, they do not yet know what causes the lens to cloud.