Have you ever wondered; how do contact lenses work?
Have you ever wondered; how do contact lenses work?If you wear lenses, or even if you don't, chances are you have asked yourself, "how do contact lenses work?" After all, it's just a little piece of plastic. It's amazing that without them, your vision can seem awful. And with a little thin lens, everything is clear. So let's take a closer look; how do contact lenses work?In their simplest form, contact lenses are nothing more than an optical lens; similar to that in a pair of eyeglasses, only much smaller and of a different material. For the nearsighted eye, the lens is a minus power.
On eyeglasses, this makes for a thin center and thick edge. The same goes for contact lenses, a very thin center and a thicker edge. The variation of the thin to thick makes up the power of the lens. For example, a -14.00 lens has thicker edges than a -2.00.The inside curve of the lens, also called the base curve, is designed for optimum fitting on the cornea. Base curves are measured in mm of radius.
For example, a base curve of 8.6 means that the lens has the same inside curves of a circle with a radius of 8.6mm.Another major factor in answering how do contact lenses work?, the diameter. Diameter is measured edge to edge, also in millimeters. The diameter is altered for physical fit and comfort. Any time the diameter is changed, the base curve needs to be revised. For example, a lens with a base curve of 8.6 and a diameter of 13.8 will be overall flatter than a lens with a base curve of 8.6 and a diameter of 15.0.To picture this in your mind, picture a circle and imagine the top quarter of the circle is a lens.
Now imagine the top half of a similar circle is a lens. Can you begin to see how different those two lenses would be?Contact lenses only work properly when they have the proper prescription and they are fit correctly. A contact lens that is too steep will not only be uncomfortable, it will also create a blurry image because of the distance between the front of your cornea and the back of the lens. A lens that is too flat will not center properly and the edges will buckle or lift off the white of the eye. Once properly fit, the lens must stay hydrated in order to work properly.
On soft contact lenses, this is accomplished simply by blinking. Think of your lids as windshield washers that constantly clean the lens. If you wear lenses, you may notice that they blur a little after long term computer use. This is directly related to the fact that a persons blink rate slows when focusing on anything up close, i.e. the computer screen.
As you can see the optical qualities, proper fitting, and constant blinking are the main factors when figuring how contact lenses work..
Steve Cogger helps thousands of contact lenses wearers find the perfect lens for their eyes. His busy New York practice specializes in all lens modalities. For more consumer information and education, www.All-About-Contact-Lenses.comContact Lenses Or Eyeglasses? Which Option Is Best For You?
Which is better, eyeglasses or contact lenses?This bout is scheduled for 5 rounds?There is no cut and dry answer to this question. While eyeglasses vs contact lenses is not a bout that would sell out Ceasar's Palace, it is of importance to most of us who rely on vision correction.Because the eyeglasses vs contact lenses debate is of such interest to so many, Let's look at the general pros and cons for each type of vision correction.I'll give you the facts and you can then decide for yourself which is best for you.Round 1 - Quality of Vision:Eyeglasses provide crisp clear and consistent vision straight ahead. There are not many variables to vision throughout the day because with glasses you are looking through a solid piece of plastic.Contacts give you good straight ahead vision, however it is not as consistent as with glasses. Soft lenses are made of plastics and water and are therefore prone to change with environmental variables. For example, air conditioners...
Contact Lenses Or Eyeglasses? Which Option Is Best For You?
Contact lenses > Contact Lenses Or Eyeglasses? Which Option Is Best For You?
Contact Lenses in Silicone Hydrogel ? the Vision of the Future?
YEARS IN DEVELOPMENT
The concept of lenses made from silicone hydrogel was first proposed over 20 years ago. The potential benefits were clear but the technological challenge was as difficult as needing to combine oil and water to produce an optically clear product. Researcher organizations have to date invested considerable academic and financial resources to achieve the high performance soft lenses of today. They have done this quite simply because they see this material as the way forward and the ultimate standard of the future.
At the time of writing, silicone hydrogel lenses are available in the USA from four manufacturers: "Night & Day" and "O2OPTIX" from CIBA Vision, "Pure Vision" from Bausch & Lomb,
and "Acuvue OASYS" and "Advance" from J&J Vision Care.
OXYGEN TRANSPORT
So what's so special about silicone hydrogel as a lens material? Essentially, the great benefit of this material is it's ability to transport...
Contact lenses > Contact Lenses in Silicone Hydrogel ? the Vision of the Future?
Petition Filed with FDA to Require Eye Care Professionals to Warn Parents that Distance Lenses Worsen Myopia
The International Myopia Prevention Association (IMPA) has filed a Petition with the U.S. Food and Drug Administration (FDA) seeking enforcement action to require eye care professionals to advise parents of children with initial myopia that distance (minus) lenses worsen myopia and that myopia may be prevented by using reading (plus) lenses for computer usage and other prolonged close work.The Petition is spearheaded by IMPA founder and author Donald Rehm in response to the absence of regulation for eye care professionals about what parents are told about the effect of distance (minus) lenses and the importance of using reading (plus) lenses for close work. A copy of the 58-page Petition and an animation explaining the basis for the Petition can be found at www.preventmyopia.org. Rehm is the author of the book: The Myopia Myth, The Truth About Nearsightedness And How To Prevent It.???Myopia is a significant health problem affecting...
Petition Filed with FDA to Require Eye Care Professionals to Warn Parents that Distance Lenses Worsen Myopia
Contact lenses > Petition Filed with FDA to Require Eye Care Professionals to Warn Parents that Distance Lenses Worsen Myopia
Acuvue Contact Lenses - Bringing Out The Best In Your Eyes!
Contact lenses are small, optical, often soft, and remarkably thin lenses placed in the cornea of one's eye. They improve the vision, and sometimes the physical appearance, of eyes. Contact lenses are usually an alternative to traditional eyeglasses, correcting a person's vision without requiring them to wear ugly, awkward bifocals. However some people with naturally good eyesight still wear contacts, solely for cosmetic reasons - to enhance or change the color of their eye.
Unlike eyeglasses, contact lenses are not easily affected by weather, are not especially fragile, and actually (in most cases) do a better job at improving a person's eyesight.
Not to mention, a glasses' framing immediately hinders a person's field of vision! This is not so with contact lenses that fit directly onto the eyeball and are practically invisible.
For those ready to scrap conventional, unfashionable eyeglasses, local eye care professionals will prescribe...
Contact lenses > Acuvue Contact Lenses - Bringing Out The Best In Your Eyes!
Your Mother Could Make Money In Forex Trading
The question would be not whether she could but rather would she enter the Forex trading market. The Forex day trading arena is a veritable snake pit ripe for scam artists to bilk money out of unwary investors. On the other hand, it is a forum for educated traders with the correct education, tools, and trading strategy to make a handsome income.Becoming a successful Forex trader basically comes down to four things; 1) attaining the correct education, 2) using Forex tools which 3) use your own...
Your Mother Could Make Money In Forex Trading forex
Contact lenses > Your Mother Could Make Money In Forex Trading
Quality Time?
From the book Spider's Big CatchGary Andersonwww.abciowa.comThere's a phrase that's become popular over the past few years that fills me with wonder. That phrase is "quality time." We've all heard it, and we all seem to accept it as a real concept. But to the average country person, that phrase is difficult to comprehend.Here's what I mean. Last summer, my 10-year-old son Cody and I spent an entire day walking the fields, checking fences. When we...
Have you ever wondered; how do contact lenses work? ladders Quality Time?
Contact lenses > Quality Time?
Home Generators
Home generators are designed to provide electricity in times of power shortages or failures for a short duration of time. Home generators not only light up the house in case of power outages but also, depending on their capacity, provide power to run appliances like air conditioners, refrigerators, furnaces, television and heaters.
Home generators are available in two types: portable and stationery or standby generators. In times of power shortages or disruption of power, small portable...
Contact lenses > Home Generators
Black Roses
The concept of using "flower language" has come a long way. Flowers, especially roses can be used to express any sentiment without having to use words. Flowers are an effective channel to correspond sentiments, which if expressed otherwise may be inappropriate. Use of black roses has always been minimal. This is attributed to the fact that in most cases it symbolizes death, hatred and farewell as they are mostly used at funerals.
Numerous radical and rebel groups have accepted the...
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Credit Repair Services vs. 'Do-It-Yourself' Credit Repair
Millions of Americans suffer because of bad credit these days, and almost all of these people turn to the Internet for help. In the past 5 years hundreds of ?internet-based' credit repair services have sprung up , preying on consumers in need of real help. Most of these companies have built less than desirable reputations by over-promising and under-delivering; all the while taking millions of dollars from those in need. For this week's article I am going to compare ?internet based' credit repair...
credit repair
Contact lenses > Credit Repair Services vs. 'Do-It-Yourself' Credit Repair