A cataract is a clouding of the lens of the eye, which is typically clear. For people who have cataracts, seeing through cloudy lenses is like looking through a frosty or fogged-up window. Clouded vision caused by cataracts can make it more difficult to read, drive a car at night or see the expression on a friend's face. Symptoms of cataracts include: Clouded, blurred or dim vision. Trouble seeing at night. Sensitivity to light and glare. Need for brighter light for reading and other activities.