Contact lenses are small, curved pieces of plastic shaped to fit your eyes to correct some vision problems, such as nearsightedness or farsightedness. Contact lenses work the same way that glasses do to improve your vision.
Contact lenses can correct most of the vision problems that glasses correct.
They can also correct some problems that glasses cannot. Often, people wear contact lenses because they do not like how they look with glasses. Also, unlike glasses, contact lenses generally do not fall off, get covered with rain, or fog up. People may prefer contact lenses over glasses if they are very nearsighted or have had cataracts removed. For them, glasses can produce uneven vision.