Contact Lens Basics

Contact lenses are an excellent vision correction option for people of all ages. According to data provided by The Vision Council in September 2014, approximately 16 percent of the U.S. population (roughly 39.3 million adults) report wearing contact lenses at least part time.

Recent advances in lens materials and care products have made contact lenses more comfortable than ever. Even people who have had problems wearing contacts in the past often are good candidates for contact lenses today.

Here are the basics you should know about modern contact lenses. For the very latest information, visit your eye care provider for a comprehensive eye exam and contact lens evaluation to see which lenses might be best for you.

Types of Contacts - By Lens Material

Basically, there are three major categories of contact lenses based on the materials they are made of:

Soft Contact Lenses

Also called hydrogel or silicone hydrogel lenses, soft contact lenses are very thin, moist and flexible. The term "hydrogel" is used because they are made of water-absorbing materials that give them a watery, gel-like feel. In fact, roughly 40 to 70 percent of the weight of a soft lens is due to the water it contains. This, combined with the fact that soft lenses are very thin, makes them immediately comfortable and very easy for most people to wear. Approximately 90 percent of contact lenses worn in the U.S. are soft lenses. Most of these are silicone hydrogel lenses, which transmit more oxygen to the surface of the eye than conventional hydrogel lenses.

Rigid Gas Permeable Contact Lenses

Also called GP or RGP lenses, these contacts are made of rigid plastics and often provide sharper, more stable vision than soft lenses. GP contact lenses also enable more oxygen to reach the surface of the eye than many soft lenses, which may decrease the risk of certain contact lens-related eye problems. But because of their rigid nature and thicker profile, GP lenses can take some time to get used to, and some people cannot wear the lenses comfortably. For these reasons, less than 10 percent of contact lenses worn in the U.S. are rigid gas permeable lenses.

Hybrid Contact Lenses

These advanced contact lenses have an optical center made of rigid gas permeable plastic, surrounded by a zone made of soft lens material. This hybrid design provides the sharp optics of a GP contact lens, with wearing comfort that is more comparable to that of soft lenses. But this combination of features also makes hybrid contact lenses significantly more costly to manufacture, causing them to be more expensive than soft lenses or GP lenses. And fitting hybrid lenses can be more challenging and time-consuming than fitting soft or GP lenses. For these reasons, less than 5 percent of contact lens wearers in the U.S. wear hybrid lenses.

Types of Soft Contact Lenses

Within the dominant category of soft contact lenses, there are many types of lenses to choose from to fit your vision correction and lifestyle needs.

Disposable lenses

Most soft contact lenses sold today are disposable lenses: you wear them for a recommended number of days, and then throw them away and replace them with a fresh pair. Most disposable lenses are designed to be discarded and replaced monthly or every two weeks. But there are also daily disposable lenses that are designed to be discarded after being worn only once, eliminating the need for lens care products. Replacing your contacts frequently decreases the risk of lens deposits that can lead to discomfort and eye infections.

Daily wear or extended wear lenses

Daily wear lenses are contacts that must be removed before sleep. Extended wear lenses are contacts that have been approved by the FDA for continuous wear (24 hr/day) for up to 30 days. Wearing contact lenses during sleep — even extended wear lenses designed for this purpose — significantly increases the risk of eye infections. For this reason, most eye doctors recommend daily wear.

Single vision or multifocal lenses

Most contact lens wearers are under age 45 and see well with conventional "single vision" lenses that have the same power for seeing objects at all distances. But for people over age 40 who need a bifocal prescription, there are a variety of multifocal soft contact lenses to eliminate (or significantly reduce) the need for reading glasses. Multifocal contact lenses are available in GP and hybrid lens designs as well.

Toric lenses for astigmatism

Toric soft lenses are hydrogel or silicone hydrogel lenses with a special design that corrects astigmatism as well as nearsightedness or farsightedness. These lenses have two types of lens power — a "sphere" power to correct nearsightedness or farsightedness, and a "cylinder" power to correct astigmatism — and a special design to keep the astigmatism power aligned properly. (GP and hybrid contacts can correct common types of astigmatism without a toric design.)

Color and special-effect lenses

Soft lenses also are available in colors to enhance the color of your eyes or change them from brown to blue, green or a variety of other attractive colors.

For an even more dramatic change in appearance, there also is a wide variety of special-effect soft contact lenses that can make you look like an alien, a vampire, or some other startling creature.

Color and special-effect contact lenses also are available without refractive power for people who don't need corrective eyewear and simply want to change the appearance of their eyes. Like contact lenses with corrective power, however, contact lenses worn for cosmetic purposes only must be fitted and prescribed by a licensed eye care provider, properly cleaned and stored, and worn and replaced as specified by the prescriber.

Which Contacts Are Best for You?

The first step in determining the best contact lenses for your needs is to have a comprehensive eye exam with your eye care provider. During this exam, your doctor will perform a number of tests that will determine if you are a good candidate for contact lens wear.

In some cases, conditions like dry eyes or allergies must be successfully treated before contact lens wear is recommended. But with today's modern lens materials and designs — in particular, with the availability of daily disposable contact lenses in several designs, including toric lenses for astigmatism and multifocal lenses for age-related loss of near vision — most people can wear contact lenses successfully, whether it's for full-time daily wear, for sports and other outdoor activities, or for special occasions.

Article ©2014, Access Media Group LLC. Source: Contact Lens Basics by AllAboutVision.com.

VISION & HEALTH NEWSLETTER COURTESY OF:

Eli Ben Moshe, O.D.
Jared Hagan,O.D.
Chris Johnson,O.D.

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SAN DIEGO, CA 92107

619-222-0559

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