Contact lens wearers have an increased risk for serious eye infections and injury to the cornea. Small objects that get into the eye may become trapped under a lens and scratch the cornea. Pinkeye (conjunctivitis) or other minor eye infections are likely to irritate your eyes and make wearing contacts uncomfortable and unsafe.

Symptoms of possible problems with contacts include redness, pain or burning in the eye, drainage, blurred vision, or sensitivity to light (photophobia). If you are having problems, remove your lenses and disinfect them. If symptoms persist longer than 2 to 3 hours after removing and cleaning your contacts, call your eye doctor.

Daily-wear lenses

Daily-wear soft lenses are removed and cleaned at night and reinserted in the morning. They take less time to get used to than hard lenses, but they are less durable.

Extended-wear lenses

Extended-wear lenses can be worn for up to a week at a time, day and night. They are then removed, cleaned, and reinserted.

Rigid gas-permeable (RGP) lenses

Gas-permeable lenses cost more than conventional hard lenses and are somewhat less durable, but they are more comfortable than conventional hard lenses. Some gas-permeable lenses are designed for extended wear (overnight, up to 7 days), although many eye specialists advise against wearing them for the extended period.

Conventional hard lenses (PMMA)

Conventional hard contact lenses are made of a stiff plastic (polymethyl methacrylate, or PMMA), which does not mold to the shape of the eye. They are inexpensive and durable, but they are the least comfortable type of contact lens. Because they reduce the amount of oxygen reaching the cornea, people who wear them are at risk of overwearing syndrome and other problems.