Not all contact lenses are the same. They are available in different forms, designed to meet different purposes. These forms can range from their “modality,” or how often you change the contact lenses-say, daily or monthly. They also fit different needs, such as contact lenses for astigmatism, longsight, nearsight, and more. Toric lenses, which are more weighted at the bottom, help correct astigmatism. Spherical lenses, which are the same all around, help correct nearsightedness and farsightedness. There are also lenses for bifocals and multifocals.