Contact lenses, often abbreviated as "contacts," are thin, curved lenses that are placed directly onto the surface of the eye. They are used to correct vision problems like nearsightedness, farsightedness, astigmatism, and presbyopia. Contact lenses provide a clear and natural field of vision without the need for traditional eyeglasses. They come in various types, including soft and rigid gas permeable (RGP), and can be disposable (daily, bi-weekly, monthly) or designed for extended wear. It's important to follow proper hygiene and care instructions when using contact lenses to maintain eye health. Regular check-ups with an eye care professional are also recommended to ensure the lenses continue to provide optimal vision correction.