Posts Tagged ‘corrective lenses’
Bifocal glasses refer to those having one section that corrects for distant vision and another section that corrects for near vision and Benjamin Franklin is believed to be the one who invents bifocals.
The reason why it is called bifocal derives from its special designation of the two lenses of different convexes posited in respectively the lower and upper half of the frame. At the very beginning the two parts were just combined directly, resulting in a sharp switch for the wearing when s/he read something from the above or from the top. Later, to solve this problem, at the end of the 19th century, Louis de Wecker developed a method for fusing the sections of the lenses together.
Bifocals were originally invented for the elders to read, and then people think that only aging people require bifocals their development of presbyopia all the time, but this is a misconception. The fact is that bifocals are also suitable for those who develop a combination of nearsightedness and farsightedness. For them, the lenses posited in the lower half of the frame are for nearsightedness correction while the upper are for farsightedness correction. Therefore, when you find young friends around you wear bifocals, do not feel surprised.
Based on the same principle, bifocals can help correct any combination of two different eyesight conditions, for example, bifocals can help correct astigmatism that is present in combination with other refractive defects.
However, every coin has two sides, bifocals lead to discomfort for the sharp vision switch from the upper to the lower or in reverse as mentioned above. Some wearers may experience from headaches and even dizziness. For the computer users, they would probably experience muscle fatigue due to the unusual angle and constant movement of the head.
Fortunately, with the progress of relative researches on it, new models come into being, the trifocal glasses and progressive glasses. As their names self-explanatory, the former consist of three corrective lenses on each side of a pair of glasses, for a total of six lenses for a pair while the latter are characterized by a gradient of increasing lens power. Both of them work similarly to bifocals do, but they aim at reducing the sharpness between different corrective lenses so as to make wearers suffer from fewer headaches from strained eyes.
Those progresses are not enough, researchers are trying to make new materials to make better bifocals, and to discovery new technologies that may provide a method which can selectively adjust the optical power of a lens.
At last, I would like to remind you that if you find yourself a need to wear bifocal glasses, you can firstly consult with an optician, who is best to be licensed, for there are different types of bifocals. With her/his help, you can decide which type of is the one for you.
Firmoo.com is the emerging online optical store selling high quality eyewear, such as prescription eyeglasses (single vision myopic glasses, reading glasses, bifocal and progressive eyeglasses etc.,), prescription sunglasses (with RX tinted lenses), prescription sports goggles. Firmoo guarantees lowest possible price in the market. Firmoo’s return and refund policy makes any purchase risk-free ones.
Article Source:http://www.articlesbase.com/vision-articles/is-it-true-that-only-aging-people-require-bifocal-glasses-1726729.html
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If you dream of freedom from glasses or contact lenses laser vision correction may be the solution for you. LASIK is the most well-known vision correction procedure, but there are several other types of laser vision correction. By reshaping your cornea, your ophthalmologist can correct nearsightedness, farsightedness, and astigmatism, giving you clear vision without the hassle of corrective lenses.
Refractive Error
Nearsightedness (myopia), farsightedness (hyperopia), and astigmatism are all forms of refractive error. Your cornea bends, or refracts, light to focus on the retina. When your cornea is misshapen the light does not focus properly. Refractive surgery reshapes your cornea, correcting how the light is bent and therefore correcting the focus of the light on the retina.
Types of Laser Vision Correction
You have probably heard of LASIK, but might not be aware that there are two types of LASIK, traditional and custom, and that there are several other forms of laser vision correction including:
- Epi-LASIK
- iLASIK
- LASEK
- InterLase
- PRK
All are performed using an excimer laser. The technique is different for each type of laser surgery, making laser vision correction possible for people who are not good candidates for LASIK.
The Precision of Today’s Laser Vision Correction
Refractive surgery is not new, but it is being constantly improved. Traditional LASIK has been used to safely and effectively correct vision for over twenty years. Custom LASIK is far more precise, and can give you even clearer vision.
In custom LASIK, Wavefront technology is used to map your eyes and guide the laser. Wavefront is also used to guide other types of laser vision correction. Wavefront diagnosis helps your ophthalmologist determine which type of laser surgery is right for you, and can detect high order aberrations that can be made worse by LASIK surgery.
Improving Your Vision and Your Life
Laser vision correction can mean freedom from corrective lenses for many patients. Those with very poor vision can achieve better corrected vision. Improving your eyesight can open up opportunities that you never had before. It may simply make things like swimming and other hobbies easier and more fun. For some, it can make essential activities, such as driving, possible. Getting rid of your glasses or contacts means waking up each morning with clear vision and never again having to worry about losing or damaging your lenses. To learn more about laser vision correction and what you can do to improve your vision please visit eyes.com today.
To learn more about laser vision correction and what you can do to improve your vision please visit Eyes.com today.
Article Source:http://www.articlesbase.com/vision-articles/laser-vision-correction-1600068.html
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Do you need to wear glasses? It seems to be a silly question, since it appears to be very easy for one to figure out. However, it is researched that eyesight problems may be more difficult than most people think, because one’s eyesight does not degenerate over one night suddenly, but in a rather slow speed, so slow that most people may be not be aware of. When one becomes nearsighted, if he or she does not adopt certain measurement to correct vision, his or her eyesight would be worse. Thus it is of importance and necessity to have a general idea on whether you need to wear glasses. Here below are some symptoms that will let you know:
Frequent tired eyes.
If you suffer from tired eyes after a short period of time’s reading or watching, and this symptom repeats for days, it should be a sign for you to make an overall eye examination on whether it results from some eye problems, or eyesight problems.
Frequent headaches or migraines.
If you frequently suffer from headaches or migraines because of over exertion by eyes, you may also need to have corrective lenses to help your vision. For except allergies, injuries or uncomfortableness, illness form of blur vision will also lead to headaches or migraines.
Sensitivity to light
If you find eye ache and are hard to recover from the change when you shift yourself from a dark room to a an area of light, it may be another sign for you that you need corrective lenses. What is more, seeing things with double images is believed one of the signs of eyesight degeneration.
Since properly identifying vision problems on your own is impossible, in order to really know if you need prescription eyeglasses, the best way and most recommended way is to visit a qualified optometrist regularly, at least once every two years. A optometrist can not only help determine whether you need glasses, but also be able to the level of your vision correction which is necessary for you to know your eyesight condition so that you are able to pay more attention to you reading habit, etc. that would affect eyesight.
However, though people are suggested to visit eye care professional regularly, most of them take no notice of it. Therefore, here I think I need to make clear the advantage of visiting optometrist: it helps you know you vision problem and then you are able to take the steps to have it corrected, or your life will be full of inconvenience, many difficulties even dangers. For example, if you are a driver, with bad vision, you hardly able to identify all traffic signs and signals which maybe cause serious accident; if you are a student, disability to see clearly what is written on blackboard is really a bad thing, which will affect your study.
As a matter of fact, having vision corrected is not that a troublesome thing, half a day at most is needed. Therefore, as for those who are very busy everyday, get a clear vision from a little time—it is fairy worth. With vision problems corrected, you could never be worried about the literally spelling the difference between life and death as a driver, and with vision problems corrected, you are able to react promptly to what teachers write on the blackboard as a student.
Another thing needs paying attention to is that those people who do not have vision correction wear glasses. For them, they just want to make themselves distinguished from others, and make themselves more cool with the ornament of glasses, however, if you wear glasses than actually you need, your eyesight will really, one day, degenerate. Therefore, to make clear that whether you really need glasses is significant.
reference
·What one must know of eyeglasses
Firmoo.com is the emerging online optical store selling high quality eyewear, such as prescription eyeglasses (single vision myopic glasses, reading glasses, bifocal and progressive eyeglasses etc.,), prescription sunglasses (with RX tinted lenses), prescription sports goggles. Firmoo guarantees lowest possible price in the market. Firmoo’s return and refund policy makes any purchase risk-free ones.
Article Source:http://www.articlesbase.com/vision-articles/do-you-need-to-wear-glasses-1591178.html