Cataracts is the clouding of the normally clear lens of your eye. The lens is what you look through. For people who have cataracts, seeing through cloudy lenses is a bit like looking through a fogged-up window. This can make it more difficult to read, drive a car (especially at night) or see the expression on a friend's face.
Most cataracts develop slowly and don't disturb your eyesight early on. But with time, cataracts will eventually interfere with your vision. Regular eye appointments will monitor the cataract and at some point, surgery will be recommended. This is a very common outpatient surgery with immediate positive results.