Contact Lenses: The Options, Contacts Not for Everyone

by Food and Drug Administration (FDA)

(Page 2 of 2)

The Options

Soft lenses are much more comfortable than rigid lenses, thanks to their ability to conform to the eye and absorb and hold water. You can get used to soft lenses within days, compared with several weeks for rigid. An added benefit is that soft lenses aren't as likely as rigid lenses to pop out or capture foreign material like dust underneath. Extra-thin soft lenses are available for very sensitive people.

While the ability to hold water increases oxygen permeability of soft lenses, it increases their fragility as well.

Rigid lenses generally give clearer vision. They can be marked to show which lens is for which eye. They don't rip or tear, so they're easy to handle.

Also, rigid lenses don't absorb chemicals, unlike soft lenses, which Saviola says are like sponges. "They'll suck up any residues on your hands — soap, lotion, whatever."

Both soft and rigid lenses offer bifocal correction. In some models, each lens corrects for near and distance vision. In others, one lens is for near vision, and the other is for distance. Middle-aged people who have good distance vision but need help for reading can get a monovision reading lens for one eye.

Soft lenses additionally come as disposable products (defined by FDA as used once and discarded) or as planned-replacement lenses.

With planned-replacement lenses, the practitioner works out a replacement schedule tailored to each patient's needs, says Byron Tart, director of promotion and advertising policy at FDA's devices center. "For patients who produce a higher level of protein in their eyes or don't take as good care of their lenses, it might be healthier to replace the lenses more frequently," he says.

Some practitioners prescribe disposables as planned-replacement lenses, which are removed, disinfected and reused before being discarded. Saviola cautions that lenses labeled "disposable" don't come with instructions for cleaning and disinfecting, while those labeled specifically for planned replacement do. Whatever lenses your practitioner prescribes, be sure to ask for written instructions and follow them carefully.

In the U.S. contact lens marketplace, 82 percent wear soft lenses, 16 percent wear rigid gas-permeable, and 2 percent wear hard. Although very few people wear hard lenses, they are available for people who have adapted to them and want them. Hard lenses are not the same as rigid gas-permeable lenses, since they do not allow oxygen transmission through the lens.

Contacts Not for Everyone

People with inadequate tearing (dry eye syndrome) usually can't tolerate contacts, says Donna Lochner, chief of the intraocular and corneal implants branch of FDA's devices center. In addition, Lochner says, "Severe nearsightedness often can't be corrected effectively with contact lenses."

Saviola notes that certain working conditions, such as exposure to chemical fumes, may be undesirable for contact-lens wearers. Contacts may be ruled out by allergy to lens-care products or by corneal problems, such as a history of viral infection of the cornea. "Extra caution," he says, "should be exercised with diabetics, because they're susceptible to infection and have trouble healing."

Cosmetic use of contacts is limited in children. Adolescence is the youngest age as a rule to consider contact lenses, says Saviola, but some practitioners do fit 9- to 11-year-olds. "You may prescribe for a younger child who has the motor skills and responsibility to handle contact lenses."

For some people who haven't been able to wear contacts and want to, implantable lenses may be an option in the future.

Doctors are studying ring segments, "shaped like parentheses," Lochner says, which are implanted in the cornea. "They flatten out the cornea, changing the shape to give the correct optical power." Lenses that are implanted inside the eye are also being studied to correct refractive error, she says.

Correcting vision is not the only use for contact lenses.

Some soft contacts are used as bandage lenses after photorefractive keratectomy laser surgery for nearsightedness. The surgery removes the outer cell layer of the cornea, creating a large abrasion on the eye. "It's excruciatingly painful," Saviola says, "if you don't have a protective covering on the cornea after the anesthetic wears off."

Collagen eye shields are used as bandage lenses to relieve pain from other abrasions or sores on the cornea. They dissolve in a couple of days.

Comparison Shopping

Companies that sell contact lenses compete stiffly for business, offering discounts and premiums such as a second set free.

But a discount for the lenses might not save you money if the price doesn't include other needed products and services, such as a thorough eye examination, lens-care kit, and follow-up visits to make sure you're adapting. A moderate cost for a package that has everything you need may be the best deal.

Before you make an appointment, ask the practitioner these questions:

• Will you give me my prescription? (You may want the prescription if you decide to go to another practitioner or order lenses from an alternate source.)
• What tests are included in the eye examination?
• What do you charge for the examination, lenses, evaluation, fitting, lens-care kit, follow-up visits, and service agreements?
• What is your refund policy if I can't adapt to contact lenses?
• How many types and brands of contact lenses do you sell?
• How much do you charge for replacement lenses?

Asking questions about any new prescription treatment is always a good idea. Like medicines, contact lenses provide benefits and pose risks. But even with the increased risk of corneal ulcers posed by extended-wear lenses, Saviola says this risk alone isn't enough to say the devices aren't safe and effective if properly used.

"If people are informed," he says, "then they're making a judgment based on available information. That's the thing we always struggle with, conveying enough information to people and having the practitioner convey enough information, so that the consumer can make an informed choice."

About the Author

www.fda.gov
FDA is A United States government body that oversees medical devices, including contact lenses, intraocular lenses, excimer lasers and eyedrops. In the US, these products must be approved by the FDA before they can be marketed.