What are contact lenses?
-
Discovery Health answered:Contact lenses correct the vision of people who cannot or don't want to wear glasses. A contact lens is a thin, transparent plastic disc that sits on the cornea. They, just like eyeglasses, are shaped based on the vision problem to help the eye focus light directly onto the retina.
Contact lenses remain in place by sticking to the layer of tear fluid that floats on the surface of the eye. Eyelid pressure also keeps them in place. With each blink, the cornea is lubricated, and any impurities that may have become stuck to the lens are washed away.
Contacts correct refractive errors, such as nearsightedness and farsightedness, that result in blurry vision when the eye doesn't focus light directly on the retina as it should.
You might think contact lenses are a modern invention, but the idea has actually been around for hundreds of years, beginning with artist and inventor Leonardo da Vinci in 1508. A wearable contact lens came along in the late 19th century, and improvements were made throughout the 20th century.
Contact lenses correct the vision of people who cannot or don't want to wear glasses. A contact lens is a thin, transparent plastic disc that sits on the cornea. They, just like eyeglasses, are shaped based on the vision problem to help the eye... More -
American Academy of Ophthalmology answered:Contacts are thin, clear disks of plastic that float on the tear film that coats the cornea, the curved front surface of the eye. The health of the corneal surface and tear film are very important to your comfort and the clarity of your vision when you are wearing contacts.
Contact lenses are used to correct the same conditions that eyeglasses correct:
- Myopia (nearsightedness)
- Hyperopia (farsightedness)
- Astigmatism
- Presbyopia
Contacts are thin, clear disks of plastic that float on the tear film that coats the cornea, the curved front surface of the eye. The health of the corneal surface and tear film are very important to your comfort and the clarity of your vision when... More -
Dr. Manvi P. Maker of NorthShore University HealthSystem answered:Contacts are lenses (clear plastic disks) placed over the cornea (front clear surface of eye). They are used to helped correct vision problems from: Myopia, Hyperopia, Presbyopia, Astigmatism. There are bifocal contact lenses available also.
It is important to have a good contact lens fitting exam before pursuing full time wear of the contact lenses, as this can help prevent complications down the road.
Contacts are lenses (clear plastic disks) placed over the cornea (front clear surface of eye). They are used to helped correct vision problems from: Myopia, Hyperopia, Presbyopia, Astigmatism. There are bifocal contact lenses available... More -
Healthwise answered:Contact lenses are small plastic or silicone discs shaped to correct an eyesight problem such as nearsightedness, farsightedness, presbyopia, or astigmatism. These are called refractive errors. They may also be used by people who have had surgery for cataracts.
After your doctor tests your vision, he or she will write a prescription for the lens you need. Your prescription may change over time.
Contacts are placed directly on the eye, where they float on a film of tears in front of the cornea. Correct design and fitting of the lenses are essential for comfort, safety and accurate correction.
Improvements in contact lenses have made them more comfortable and easier to wear. Millions of people wear contact lenses, and most wear soft lenses. For these people, contact lenses offer a relatively safe and effective way of correcting vision problems.
Several types of contact lenses are available to correct nearsightedness. Contact lenses are needed after cataract surgery if an artificial lens cannot be implanted in the eye.
Hard (rigid) lenses- Conventional hard (polymethyl methacrylate, or PMMA) lenses are made of a stiff plastic. They correct vision with no distortion, but they are the least comfortable type of contact lens.
- Rigid gas-permeable (RGP) lenses are more comfortable than conventional hard lenses. Some gas-permeable lenses are designed to be worn overnight and for up to 7 days.
- Daily-wear lenses are removed and cleaned at night and reinserted in the morning. You'll need to buy new ones at least once a year.
- Extended-wear lenses can be worn for up to a week at a time, day and night. But extended use may be uncomfortable, and it increases the risk of damaging the eye.
- Disposable lenses (daily and extended-wear) may be worn for up to several weeks and then discarded.
Contact lenses are small plastic or silicone discs shaped to correct an eyesight problem such as nearsightedness, farsightedness, presbyopia, or astigmatism. These are called refractive errors. They may also be used by people who have had surgery... More
