Contact Lens Types
Contact lenses provide many of those with vision problems a virtually invisible alternative to eye glasses. Contacts can be used to correct common vision problems such as nearsightedness, farsightedness, astigmatism and even presbyopia.
As the popularity and demand for contacts has increased, there have been several technological advances that have been made. Today there are several types of lenses available on the market and each type offers the wearer a different advantage.
The design of each type of contact lens is based on one of the following factors:
- Material used to make the lens
- Length of time lens can be worn without removal
- How often lens should be disposed
- Design of the lens
The main category used to determine a lenses type is the material used to make the lenses. These types of lenses include hard or rigid lenses, soft lenses and rigid gas permeable lenses.
Hard (Rigid) Lenses – were the first contact lenses introduced to the market in the 1960’s, but are rarely used now. Hard lenses are made from Plexiglas or Lucite and are the least comfortable type of lenses available.
Soft Lenses – are the most commonly used contact lenses. While soft lenses are larger than your iris, the gel-like, water-containing plastic used to make them provides a more comfortable wearing experience.
Rigid Gas Permeable Lenses – are made from rigid, waterless plastics that allow oxygen to pass through to your eyes. View Rigid Gas Permeable Contact Lenses to learn more.
Many soft contact lenses are also categorized by the length of time that the lenses can be worn before they need to be removed from the eye.
Daily Lenses – are designed to be worn during the day and removed each night.
Extended Wear Lenses – can typically be worn overnight for seven consecutive days without removing them.
Soft contacts may also be categories by how often each pair of lenses can be worn before discarded. Disposable lenses can range from daily to monthly replacement.
Daily Disposable –Daily Disposable Contact lenses are replaced each day.
Weekly Disposable –Weekly disposable contact lenses are replaced each week.
Monthly Disposable – Monthly Disposable contact lenses are replaced each month.
Contact lenses are also categorized by the design of the lens which affects the curvature of the lens to accommodate the correction of different vision problems. The types of lenses categorized by design include spherical, bifocal, toric and orthkeratology.
Spherical – typical round lenses that are used to correct nearsightedness and farsightedness.
Bifocal and Multifocal – Bifocal contact lenses contain two or more powers per lens which correct for near and far vision. To find more about bifocal and multifocal lenses, check out the article Are Bifocal Contact Lenses Right for You?
Toric – Toric Contact lenses contain two powers, one to correct the astigmatism and the other to correct either nearsightedness or farsightedness. To learn more about toric lens, read Correcting Astigmatism with Toric Lenses.
Orthkeratology – are worn during the night to reshape the cornea in an effort to correct nearsightedness.
With so many types of lenses available on the market today, most people who need vision correction is able to do so by wearing contact lenses. Since your eye care practitioner will determine which type of contacts are best suited for you when he writes your lens prescription, you can be sure that you will purchase the right type whenever you order your contacts. If you need information on how to clean your lenses and keep them in good shape, take a look at the Proper Contact Lens Care article.