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A contact lenses is a thin, clear disks of plastic that floats on the surface of the eye. Contact lenses correct vision like eyeglasses do, and are safe when used with care. People with otherwise healthy eyes and the ability to handle and care for them may opt for contact lenses. Contact lenses are used to correct the same conditions that eyeglasses correct:
There are two general types of lenses: hard and soft. The hard lenses most commonly used today are rigid gas-permeable, or RGP. They are made of plastics and other materials such as silicone or fluoropolymers. Hard lenses hold their shape, yet allow the free flow of oxygen through the lenses to the cornea. RGP lenses may be the best choice when the cornea has enough astigmatism (is shaped like an egg instead of an orange) that a soft lens will not provide sharp vision. They may also be preferable when a person has allergies or tends to form protein deposits on his or her contacts. Soft lenses are the choice of most contact lens wearers. These lenses are comfortable and come in many options for how you wear them. Daily wear lenses are the least expensive, are removed nightly and are replaced on an individualized schedule. They should not be used as an extended-wear lens. Extended wear lenses are worn overnight but are removed at least weekly for thorough cleaning and disinfection. They are being recommended less frequently, since there is a greater risk of corneal infection with any overnight wear of contact lenses. Disposable wear lenses are more expensive, but convenient. They are removed nightly and replaced on a daily, weekly or monthly basis. Disposable lenses are sometimes recommended for people with allergies and for those who tend to form deposits on their lenses. Colored contact lenses can change the appearance of your eye color. Toric soft contact lenses can correct astigmatism, although sometimes not as well as RGP lenses. They usually cost more than other contact lenses. Any lens that is removed from the eye needs to be cleaned and disinfected before it is reinserted. Your doctor will discuss the best type of cleansing system for you, depending on the type of lens you use, any allergies you might have and whether or not your eye tends to form protein deposits. Care of contact lenses includes cleaning their case, since it is a potential source of infection. The case should be rinsed with contact lens solution and allowed to dry. Daily wear lenses should not be worn while sleeping. Risks Lenses that are not properly cleaned and disinfected increase the risk of eye infection. Any lens that is removed from the eye needs to be cleaned and disinfected before it is reinserted.
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