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Topics on this page include:

What are contact lenses? | Advantages of wearing contact lenses instead of glasses | Disadvantages of contact lenses | Types of lenses | Dos and don'ts | Who should/shouldn't wear contacts | Contacts and presbyopia | Complications | Warning signs | Taking care of your contacts | Contacts and cosmetics

What are contact lenses?

Contact lenses are small, curved, thin plastic discs that cover the cornea. They are used to correct myopia (near-sightedness), hyperopia (far-sightedness), astigmatism (distorted vision), and presbyopia (aging eyes).

Twenty-five million people in the U.S., two-thirds of whom are female, wear contacts. Ten percent are under age sixteen, thirty percent are ages seventeen to twenty-four, and fifty percent are ages twenty-five to forty-four.

Most contact wearers are nearsighted. Fifty percent wear daily wear soft lenses. Sixteen percent wear disposable soft lenses, ten percent wear extended wear soft lenses, eight percent wear planned replacement lenses, fifteen percent wear rigid gas-permeable lenses, and one percent wear standard hard lenses. Eight percent of contact lens wearers go to an optometrist for their eye care, and more than ninety-seven percent of practicing doctors of optometry offer contact lens services.

Advantages of wearing contact lenses instead of glasses?

There are several advantages to wearing contact lenses instead of glasses. When compared to eyeglasses, contact lenses generally offer better sight. They move with your eyes and allow a natural field of view. There are no frames to obstruct the field of vision and contacts greatly reduce the distortions sometimes found with glasses. Contacts don't fog up like glasses, nor do they get splattered by mud or rain. In addition, contact lenses don't get in the way of a person's activities. Finally, many people feel they look better in contact lenses than glasses.

Disadvantages of contact lenses

There are some disadvantages to wearing contacts instead of glasses. When compared to glasses, contact lenses require a longer initial examination and more follow-up visits in order to maintain eye health. They also require more time for maintenance. Successful contact wearers must clean and store their contacts properly, adhere to their wearing schedules, and make appointments for follow-up care. A person who is wearing disposable or planned replacement lenses must carefully follow the schedule for throwing away used lenses.

Types of lenses

There are several different types of contact lenses.

Hard lenses

Hard lenses, made from a hard plastic material, were the first contact lenses available. They don't allow oxygen to reach the cornea, so they are used by only about one percent of all contact users today.

Hard contact lenses were inexpensive, easy to care for, and corrected astigmatism well. However, they took a long time to get used to and, after years of wear, caused damage to the cornea. In addition, they are more mobile and may slip up and hide under the eyelid. They are rarely used today.

Daily wear soft lenses

Daily wear soft lenses are thin polymer-plastic lenses that conform to the shape of the eye. They are made of soft, flexible plastic that allows oxygen to pass through to the eyes.

Daily wear soft lenses have several advantages over other types of contacts. They are easier to fit and wear than hard lenses, and they are more comfortable. They have a short adaptation period, and they allow oxygen to pass through to the cornea. Daily wear soft lenses are more difficult to dislodge than rigid gas-permeable lenses. They are available in tints and bifocals, and are great for a person with an active life style.

There are some disadvantages to daily wear soft lenses. They must be cleaned and sterilized once a day, usually at night. The cost of supplies for cleaning and sterilization is ongoing. Daily wear soft lenses get dirty easily and must be replaced about once a year. They don't correct high degrees of astigmatism very well, and a person's vision may not be as sharp as with rigid gas-permeable lenses. The patient must also make regular office visits for follow-up care.

Special lenses called toric lenses are now available to correct mild to moderate astigmatism.

Rigid gas-permeable lenses

Rigid gas-permeable lenses are made of rigid plastic, but allow oxygen to pass through to the cornea.

They have several advantages over other lenses. They allow excellent vision, and are comfortable for most people after a short period of adaptation. Rigid gas-permeable lenses require less rigorous maintenance than soft lenses and there is less chance of infection. Rigid gas-permeable lenses can correct a wide range of vision problems, including corneal astigmatism. They are easy to put in and last for a long period of time without being replaced. They are available in both tints and bifocals.

There are a few disadvantages to rigid gas-permeable lenses. They are less comfortable than soft lenses and they must be worn consistently to maintain adaptation. They slip off the center of the eye more easily than some lenses, and it is easy for specks of dust to get under the lens causing short periods of tearing and irritation. Gas-permeable lenses allow protein build-up causing discomfort, blurring, and intolerance. They also require special cleaning solutions and office visits for follow-up care.

Extended wear lenses

Extended wear lenses may be soft or rigid gas permeable lenses. They are not removed at night, and can be worn continuously for seven days. They are often used with babies when they need to wear corrective lenses because they don't have to be changed often.

Extended wear lenses don't correct all vision problems, and the risk of complications is higher than for daily wear lenses. In fact, there is a ten-fold increase if they are worn consistently overnight. They also require regular monitoring and professional care.

Extended-wear disposable lenses

Extended-wear disposable lenses are soft lenses that are worn for an extended period of time - from one to six days, and then they are discarded. They require little or no cleaning, and if the wearing instructions are followed, there is minimal risk of eye infection. Extended-wear disposable lenses are available in tints and bifocals. If a contact lens is lost or damaged, spare lenses are readily available.

There are a few disadvantages. They don't correct all vision problems, and a person's vision may not be as sharp as with rigid gas-permeable lenses. In addition, they are more difficult to handle.

Planned replacement disposable lenses

Planned replacement disposable lenses are soft daily wear lenses that are replaced on a planned schedule - most often either every two weeks, monthly or quarterly.

They require simplified cleaning and disinfecting and are discarded or replaced weekly. This reduces the chance of infection or deposit formation. They are good for eye health and are available in most prescriptions.

Their disadvantages are similar to those of soft lenses. Wearers may not experience as sharp a vision as they would with rigid gas-permeable lenses. Planned replacement disposable lenses don't correct all vision problems and they may be more difficult to handle.

Dos and don'ts

To wear contacts successfully, the user must follow several common sense guidelines.

Do's

• Listen and watch closely when your eye care professional gives instructions and demonstrates how to insert and remove contacts and how to care for the lenses.
• Practice lens care routines in your doctor's office.
• Follow lens care and handling instructions carefully.
• Schedule follow-up visits to your eye care provider during and after the adaptation period. This is important to maintain good eye health and to be able to wear contact lenses safely.
• Be careful when handling, cleaning, and disinfecting your lenses and cases. Wash your hands thoroughly before handling the lenses, especially if you are a smoker. Handle your contact lenses over a clean towel. If you drop a lens, it will remain clean and undamaged.
• When you remove your lenses, clean, rinse, and disinfect them. The cleaning solution loosens debris, but it doesn't clean or disinfect the lenses. A disinfecting solution will kill microorganisms that can cause eye infections.
• After inserting your lenses, empty the soaking solution from the case and rinse it with saline or disinfecting solution. Do not use tap water. Tap water contains microorganisms and other contaminants that can cause problems. Dump the rinsing solution out of the case and leave the case open to air dry. Sealing the case provides a moist environment where bacteria can develop.
• Store your lenses in the their case and keep the case clean. Replace the lens case every six months. Cases can harbor infection.

Don'ts

• Don't use homemade saline solutions. They have been linked to serious eye infections.
• Don't use cream soaps. They can leave a film on your hands that can be transferred to the lenses.
• Don't put contact lenses in your mouth or wet them with saliva. Saliva is full of bacteria and is a potential source of infection.

Who should/shouldn't wear contacts

Contacts can be worn at any age, even by infants. If a child wants to wear contacts, he or she should be old enough, mature enough, and disciplined enough to care for the contacts. Teenagers usually have the discipline to care for their contacts. It is not necessary for a child's eyes to stop changing and growing in order to wear contacts.

Conditions that can keep people from wearing contacts include frequent eye infections, severe allergies, dry eyes, a dusty or dirty work environment, and the inability to handle and care for lenses properly.

Contacts and presbyopia

Presbyopia is the condition found in middle aged and older people where the lenses inside their eye loses their ability to change shape and bring close objects into focus. People who are over forty and wear glasses generally wear bifocals to correct for this condition.

Contact wearers often select Monovision lenses. One lens has a prescription for reading and the other a prescription for distance. The brain adjusts and learns to see as if both eyes had the same correction. Most people can adapt to the two different contacts without difficulty.

Some contact wearers who are suffering from presbyopia wear a combination of contact lenses and reading glasses. Bifocal contacts lenses are also available.

Complications

There are some complications that can arise from wearing contacts. The first of these is damage to the cornea. Damage sometimes occurs from overuse. Wearing contacts for too long starves the cornea of oxygen. The result is blurry vision, pain, excessive tearing, redness, and light sensitivity. If these symptoms occur, contact users should remove their lenses immediately.

Occasionally contact wearers experience corneal vascularization. Tiny blood vessels grow into the clear tissue of the cornea and cause cloudiness because of the lack of oxygen. The contact user may need to switch to a different type of contact lens or quit wearing contacts.

Users of standard hard lenses sometimes experience corneal warping. The cornea changes shape because of a lack of oxygen, and the result is uneven or fluctuating vision.

Giant papillary conjunctivitis is a common allergic disorder found in users of soft lenses. Symptoms include itchy eyes, a discharge, excessive movement of the lenses, and blurred vision. This condition is found more commonly in people who have old lenses or whose lenses have developed a protein layer on the surface.

Bacterial or fungal infections also occur occasionally. A corneal infection that results in a corneal ulcer is rare, but serious, and is usually associated with extended-wear soft lenses.

Warning signs

There are several warning signs that indicate there may be a problem associated with the wearing of contact lenses. If any of these occur, the user should remove his or her contacts. If the symptoms don't go away, the contact user should contact an eye professional.

• Irritation of the eye or redness.
• Blurred or fuzzy vision, especially if it begins suddenly.
• Uncomfortable lenses.
• Pain in and around the eyes.

Taking care of your contacts

• Wash, rinse and dry your hands before handling lenses.
• Use mild soap and a lint-free towel.
• Handle and insert or remove lenses before applying or removing makeup.
• Never use tap water, saliva, or homemade solutions to clean or wet lenses.
• Use quality lens care products according to manufacturer's directions. Don't reuse solutions.
• Clean your lens case daily with sterile rinsing solution and air dry it.
• Replace your case every three months.
• Clean and disinfect your contacts every day to kill germs and prevent infections.
• After you put your contacts in your eyes, rinse the case with saline solution and let it air dry.
• Always use store-bought saline solutions. Eye infections have been linked to homemade solutions.

Contacts and cosmetics

Many women find they have difficulties with their contacts associated with applying their makeup. Some of the following tips may help alleviate problems associated with contacts and makeup.

• Put on soft contact lenses before applying makeup.
• Put on rigid gas-permeable lenses after applying makeup.
• Avoid lash-extending mascara. It contains fibers that can irritate the eyes.
• Avoid waterproof mascara. It can't be removed easily and may stain contacts.
• Remove lenses before removing makeup.
• Choose an oil-free moisturizer.
• Don't use hand creams or lotions before putting on your contacts. They may leave a film on the contacts.
• Use hairspray before putting on your contacts. If you use hairspray while you have your contacts on, close your eyes during spraying and leave them closed for a few seconds afterwards. Walk away from the area where you sprayed.
• Blink your eyes frequently while under a hair dryer or while using a blow dryer. This will help distribute tears in your eyes and keep your eyes from getting too dry.
• Keep false eyelash cement, nail polish and remover, perfume and cologne away from lenses. They can damage the plastic.
• Choose water-based, hypoallergenic liquid foundations. Cream makeup can leave a film on your lenses.