What you need to know
What do contact lenses do?
Contact lenses are small prescription lenses, worn in “contact” with the eye. They are designed to correct refractive errors and maintain ocular health. They float on the tear film layer on the surface of the cornea.
Modern contacts are much more than small eye glass lenses that fit onto your eyes. They do, however, function much like regular eye glasses—refracting and focusing light so that objects appear clearly. Since the lenses stick to the tear fluid on your eye surface, they move naturally with you. This is but one advantage contacts have over glasses.
Types of contact lenses
Types of contacts are not all 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 contacts---say, daily, every two weeks, or monthly. They also fit different needs, such as contacts for astigmatism, contacts for nearsightedness, and more.
Contact lenses come in different strengths or “diopters.” If you wear contacts, take a look at their box or your prescription. You’ll see either plus or minus signs, followed by numbers. Without getting too in-depth, these convey the shape of the lenses. Different shapes correct different vision problems.
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 monovision, bifocals, and multifocals.