What are contact lenses?
Contact lenses are small, curved pieces of plastic shaped to fit your eyes to correct some vision problems, such as nearsightedness or farsightedness. Nearsightedness means that you see close objects clearly, but distant objects are blurry. Farsightedness is when you see distant objects clearly, but close objects are blurry.
Contact lenses float on the tear film in front of the cornea (the clear outer layer on the front of the eye). Contact lenses can correct most of the vision problems that glasses correct. They can also correct some problems that glasses cannot.
When are they used?
Often, people wear contact lenses because they do not like how they look with glasses. Contact lenses may be more practical than eyeglasses if you participate in sports or work at jobs where glasses could get in the way. Also, contacts give better peripheral (side) vision than glasses do.
People may prefer contact lenses over glasses if they are very nearsighted or have had cataracts removed. For them, glasses can produce uneven vision. Contact lenses may also provide better vision for people whose corneas have been damaged by disease or injury.
What are the main types of contact lenses?
The two main types of contacts used today are soft contact lenses and gas permeable (sometimes called rigid or hard) contact lenses.
- Soft contact lenses are made of special plastics that absorb water. They absorb liquids and are kept moist so that they stay flexible and mold easily to the cornea. For many people, they are the most comfortable type of contacts.
- Gas permeable lenses are made of durable, unbending plastic. They are easier to care for than soft contact lenses. Gas permeable lenses allow more oxygen to reach the cornea than the original hard lenses.
Both gas permeable and soft contact lenses can be made into bifocals. Also, both types can be tinted either for use as sunglasses or for cosmetic reasons.
How can I get contact lenses?
You need a thorough eye exam by an eye doctor who will:
- measure the curvature of the cornea, check the position of your eyelids, and check the health of the surface of your eye and eyelids
- suggest either gas permeable or soft lenses
- teach you how to put on or take off your lenses
- review with you how to best care for your lenses
- check your eyes regularly after you begin wearing your lenses full time
When you first start wearing contacts, you may feel a slight discomfort when they are in your eyes. This is normal. If you have any pain in your eyes that does not go away after removing your contacts or that returns each time you wear your contacts, see your eye care provider. You should have checkups of your eyes and lenses 1 week, 2 weeks, 1 month, 6 months, and 1 year after you first get them. If you have any problems, you may need to go for checkups more often.
What precautions should I take with contact lenses?
- When you first start wearing contacts, carefully follow the break-in schedule prescribed by your eye care provider.
- Wash your hands with soap and water before you put in or take out your contacts.
- Do not wear your contacts while swimming. Soft lenses absorb chemicals from the water. Gas permeable lenses can float out of your eyes.
- Do not wear contacts when you sleep. Sleeping with your lenses in your eyes may damage your eyes by keeping the cornea from getting enough oxygen. Also, it places you at risk for infection. For extended-wear lenses, follow your eye care provider's instructions about how long you can safely keep the lenses in your eyes.
- Always put your contacts in your eyes before you put makeup on. Use water-soluble makeup. Do not use lash-building mascara, because particles may get into your eyes. If you put eyeliner between your lashes and your eyes, you may discolor soft lenses permanently.
- Do not put contact lenses in your mouth to moisten or clean them. It may increase your risk of eye infection.
- Do not use eyedrops without your eye care provider’s approval. Some eyedrops could make an infection worse.
- See your eye care provider promptly if you have burning, redness, pain, unusual light sensitivity, or blurred vision.
What are some problems with contact lenses?
You may find it hard to wear contact lenses if you have:
- very irritated eyes from allergies or exposure to dust or chemicals at your job
- an overactive thyroid gland, uncontrolled diabetes, a tremor, or severe arthritis in your hands
- dry eyes because of pregnancy, birth control pills, diuretics, antihistamines, or decongestants
- an eye disease that affects the health of the surface of the eye
Possible problems include:
- eye infections
- allergic reactions to lens care solutions and particles on or in the lenses
- inflammation (redness) of the eye
- scratched cornea
- a change in the shape of your cornea
- abnormal blood vessels growing into the cornea
Reviewed for medical accuracy by faculty at the Wilmer Eye Institute at Johns Hopkins. Web site: http://www.hopkinsmedicine.org/wilmer/
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Published by RelayHealth.
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