A contact lens is a thin plastic or glass lens that is fitted over the cornea
of the eye to correct vision problems such as myopia, hyperopia or astigmatism.
There are two general types of contact lenses--soft and rigid gas permeable
hard lenses. They both have unique benefits and some may even come with a
colored tint, ultraviolet protection or as bifocals.
Soft lenses are made of a soft plastic and are more comfortable than hard
lenses because they hold more water. Many soft contact lenses also provide UV
protection. They are usually disposable and can be thrown away after a short
period of use, generally every two to four weeks or daily, depending on the type
of lens prescribed. Being able to have a fresh pair of lenses means less chance
of infection, less cleaning, and more comfort, especially for people whose eyes
naturally produce more protein that clouds lenses.
While most people choose soft contact lenses because of their benefits, there
are also some disadvantages. Soft lenses easily absorb pollutants like lotion or
soap from your hands, which can irritate your eyes. They are also more fragile
than hard lenses and can rip or tear easily.
The most recent type of soft contact lenses to hit the market, include Daily
Disposables and New Silicone Extended Wear Disposables.
These contacts are only worn once and then thrown away. The benefits of Daily Disposables include
never having to clean your contact lenses, convenient replacement schedule,
and reduction of dry eye and irritation related to contact solutions. If you
are an allergy sufferer, these are the contacts for you.
Silicone extended wear disposables
These are made with a new material that can
be worn for up to 30 nights and days. The new silicone material also prevents
deposit build up and reduces dry eye irritation.
Rigid gas permeable hard lenses
Rigid gas permeable lenses, or hard contact lenses, are more rigid than soft
lenses and therefore more durable. Unlike older versions of hard lenses, rigid
gas permeable lenses are made with silicone polymers, allowing oxygen to
circulate to the cornea of the eye. Compared to soft contact lenses, hard
contacts maintain their shape better and offer clearer vision for some types of
corrections. They are also extremely durable and easy to take care of. However,
if you are considering this type of hard contact lens, you should know that:
- There is a 10-15 times greater risk
of developing corneal ulcers, a serious infection, which may damage your
vision if not treated.
- Sleeping in extended wear contacts
may decrease flow of oxygen to the cornea, which can damage you vision.
- Undesirable reshaping of the cornea
- The amount of time needed to adjust
to hard contacts is often repeated after not wearing them for as little as a
day. Therefore, in order to achieve maximum comfort, you have to wear the
contact lenses every day.
Bifocal contact lenses are designed to give good vision to people who have
a presbyopia. These lenses work much like bifocal eyeglasses, having two
powers on one lens: one to correct distant vision and another to correct near
vision. Bifocal contacts come as both soft and rigid gas permeable lenses.
Toric contact lenses
Toric lenses are special lenses for people with astigmatism. They made from
the same material as other contact lenses and come in soft or rigid gas
permeable forms. Like bifocal lenses, toric lenses have two powers, one for
the astigmatism and another for myopia or hyperopia if either of these
conditions is also present.
Colored tints can be added to certain contact lenses that make them
easier to see when handling, enhance or change eye color, and improve contrast
for outdoor sports, like golf and softball. Contact lenses with novelty
effects are available, but should still be handled and cared for like
How do I know which type of contact lens is right for me?
The type of vision correction needed, your lifestyle, and expense will all
play a role in your eye care specialist’s recommendations for the type of
contact lenses that you should wear.
Who should not wear contacts?
Contacts are generally not prescribed for people who:
- Do not produce enough tears
- Are constantly exposed to fumes
- Have a history of viral infection of the cornea
- Are under age 9
Where do I go to get contacts? Can I order them through the mail?
Contacts can be purchased from a variety of places including your eye doctor, a store
specializing in optical wear, through mail order, or over the Internet.
There is no one ideal place to purchase contacts--it is a matter of
individual preferences or need. Before you begin to shop around for contact
lenses, be aware that you first must have your contact prescription.
When shopping for contacts, cheaper does not always mean better. Some other
things to keep in mind when pricing contacts include:
- Convenience: Is customer service
readily available to assist you if need be? Does the company have policies
with regard to lenses damaged during shipping?
- Insurance coverage: Be sure to contact your insurance company about
coverage of contact lenses. Many plans do not cover specialty lenses,
such as colored lenses.
- Availability: Are your lenses in
stock? Are you willing to wait longer if necessary for your lenses to arrive?
Regardless of where you get your contacts, it is important to regularly get
eye exams so that any changes in your prescription can be noted and that the overall health of your eyes can be maintained.
© Copyright 1995-2009 The Cleveland Clinic Foundation. All rights reserved
This information is provided by the Cleveland Clinic and is not intended to replace the medical advice of your doctor or health care provider. Please consult your health care provider for advice about a specific medical condition. This document was last reviewed on: 3/5/2009...#10737