Contact lenses, compared to eyeglasses, generally offer better sight; contact lenses move with the eye, allow a more natural field of view, do not obstruct vision, and greatly reduce distortions.
CONTACT LENSES FAQ
What vision problems can be corrected with contact lenses?
Contact lenses can be used to correct nearsightedness (myopia), farsightedness (hyperopia), astigmatism, or a combination of those vision problems.
What materials are used to make contact lenses?
Various materials are used, depending on the type of contact lenses. There are three contact lens groups: soft contact lenses, gas permeable lenses, and hard lenses.
The most common type of contact lenses are soft contact lenses, which are made from gel-like, water-containing plastics. From the time soft contacts were first used in 1971 until a few years ago, they were made from hydrogel plastics. Now, most soft contact lenses are made from silicone hydrogel, a product which allows more oxygen to reach the eye.
Gas permeable contact lenses, also known as GP, RGP, or oxygen-permeable lenses, are made from rigid, waterless plastics (silicone composition) that allow lots of oxygen to pass thru the lens to the eye, even more so than most soft contact lenses. They are sometimes called hard lenses, although they are vastly different from the old style of hard lenses.
The original hard lenses are a type of contact lens that preceded soft contacts and gas permeable contacts, but are now outdated. They were made from PMMA, also known as Plexiglas or Lucite. These contact lenses were uncomfortable to wear and did not allow oxygen to pass through to the eye.
What are the different types of soft contact lenses?
Soft contact lenses are available as either daily wear contacts (contacts you remove before sleeping) or extended wear contacts (contacts you can wear overnight).
How long can I keep in extended wear contact lenses?
Most extended wear contact lenses can be worn up to seven days without removal, although there are also a couple of brands that are approved for up to 30 days of continuous wear.
Why can some contact lenses be worn for a longer period of time than others?
The material used to make contact lenses affects the length of time they can be worn. Materials that allow more oxygen to pass thru the contact lens to the eye can be worn for a longer amount of time before removing them. Oxygen is necessary for healthy eyes.
Is it safe to sleep in contact lenses?
While some contact lenses are approved for overnight wear, sleeping in contact lenses can also increase the risk for infection and other complications. Wearing contact lenses while sleeping diminishes the amount of oxygen that reach the eye and provides a thriving environment for potentially dangerous germs that get lodged under the contact lens.
Although extended wear lenses are approved for overnight wear, many wearers still remove them most nights in order to have the option of wearing them overnight on an occasional basis. This allows them to avoid the risk of sleeping in contacts on a daily basis, yet allow them to wear them for times when it might be inconvenient to remove them, such as a stay away from home.
Why do I need to get another prescription for contact lenses if I already have a prescription for glasses?
The contact lens prescription contains additional information that is not relevant on a prescription for glasses. Contact lenses must fit the shape of the eye and be a healthy match for your eyes. The contact lens that is best for your eye will vary based on the refractive error, size, shape, and physiology of the eye, including factors such as astigmatism or dry eye syndrome, as well as the features of the lens itself (i.e., overnight wear, color, special effects).
When you get a prescription for contact lenses, it specifies the power (vision correction), the size (diameter), and shape (curvature) of the lens, as well as the exact type and brand of contact lens.
Do I need a prescription for special-effect contact lenses?
All contact lenses, including special-effect contacts used for Halloween costumes, are considered medical devices and require a prescription from an eye care professional, even if you don’t need vision correction. If they are not fitted to your eye or cared for properly, they can cause eye infections and more serious vision problems. Special-effect contact lenses must be cleaned and disinfected like any other contact lens and must never be shared with anyone else.
Can a contact lens get lost behind my eye?
Although contact lenses sometimes get stuck under the eyelid, they cannot permanently disappear behind the eye. A thin membrane protects the eye and prevents contact lenses from slipping in back of the eye. If you have trouble getting a contact lens out of your eye, you can try using rewetting drops to moisten the eye and blinking several times to reposition the lens, or, at worst, have your eye doctor help you get it out.
Can I use water to clean my contact lens?
Water should never be used to clean or store your contact lenses. Your contact lenses should only be cleaned and stored in suitable contact lens solution for proper cleaning and disinfecting. This affects both comfort and safety. Cleaning your contacts with water will not only affect the quality of the lens, but more importantly the microorganisms in water can lead to serious eye infections.
However, you may use tap water to clean your contact lens storage case when not in use. Rinse the case with hot tap water and then let it dry.
Is there anything I can do if my eyes feel dry when wearing contacts?
Occasional dry eyes symptoms can often be relieved with over-the-counter eye drops. Ask your eye doctor to recommend a product, as not all drops and lenses are compatible.
If you experience dry eyes on a regular basis, talk to your eye doctor. Some contact lenses are better suited to people with dry eyes than others.
Can I wear my contact lenses if I go swimming?
It is best if you don’t wear your contact lenses in swimming pools, hot tubs, showers, or natural waterways as the bacteria in the water can adhere to your lenses and cause infections. If you do swim in your lenses, however, make sure you wear goggles and that you disinfect your contact lenses immediately afterwards.
