So How Do Sunglasses Work?

!±8± So How Do Sunglasses Work?

There are two reasons to wear sunglasses. The first reason is if you don't like the bright sun shining in your eyes, as the dark surface of the sunglasses helps to block out bright light and make the world appear darker. The second is that the sun's ultraviolet rays can be harmful in the long term, causing all sorts of problems with your eyes including loss of eyesight and eye cancer. Good sunglasses protect against this, as their lenses filter out most of the harmful UV rays.

So how do sunglasses work? The darkening effect is a very simple one: looking at the world through tinted lenses makes it seem darker to you - even though the effect is really just an optical illusion, it can help you if exposure to bright sunlight tends to give you a headache or cause you to squint.

The UV-filtering effect, however, is more complex. UV-filtering lenses are coated with special chemicals that allow light to pass through them, but reflect away UV. UV rays are basically high-frequency light waves, which means that the chemical structure has to be built to deflect higher frequency light while allowing through lower frequency light. This is difficult science, and the materials needed to do it are expensive.

The most complicated sunglasses of all are prescription sunglasses. These are sunglasses that not only protect from light and UV, but also work like normal glasses to correct your eyesight. For this to work, it requires that normal vision-correction glasses are taken, tinted and coated with UV-reflecting chemicals - a complicated three-step process. However, all the ingredients work together flawlessly, to produce sunglasses that are wearable by people who need their vision corrected all the time. It is even possible to buy clear tinted lenses that fit over the top of your normal glasses, effectively a do-it-yourself way of making prescription sunglasses.

So How Do Sunglasses Work?

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Fitovers Eyewear - Nagari Collection - Torana - Amber Sky/polarized Amber - Designed to Fit Over Small Oval Shaped Frames Not Exceeding 143mm X 42mm - 5 - 5/8" X 1 - 1/2"

!±8± Fitovers Eyewear - Nagari Collection - Torana - Amber Sky/polarized Amber - Designed to Fit Over Small Oval Shaped Frames Not Exceeding 143mm X 42mm - 5 - 5/8" X 1 - 1/2"

Brand : Fitovers | Rate : | Price :
Post Date : Nov 06, 2011 18:51:14 | Usually ships in 1-2 business days

Splotch GuardTM An oleophoibic treatment that prevents fingerprints and smudges from adhering to the surface of the lens Duo Hard CoatTM Provides multiple impact and scratch resistant treatments protecting your lenses for years to come. Flash-ReflectTM A subtle flash mirror treatment that reflects bright light away when in intense light conditions. Flash-ReflectTM gives the lenses a glass-like appearance and hides your prescription eyewear. BlueLight FilterTM All PDXTM Lenses filter out varying degrees of blue light. PDXTM Polarized Amber 16: Luminous Transmittance Value (Tv) = 16% This lens blocks 99.9% of all reflected glare while allowing 16% of visible light to pass through the lens to your eye. PDXTM Amber lenses have a medium to dark brown/yellow tint that is ideal for bright sunny days and overcast conditions. PDXTM Polarized Gray 15.5: Luminous Transmittance Value (Tv) = 15.5% This lens blocks 99.9% of all reflected glare while allowing 15.5% of visible light to pass through the lens to your eye. PDXTM Gray lenses have a medium to dark tint that allow colors to be seen in their most natural state.

• Designed to fit over small oval shaped frames not exceeding 143mm x 42mm - 5 - 5/8" x 1 - 1/2"
• PolarvueTM Polarized Lenses
• Wrap around 100% UVA & UVB Protection
• Hypo-allergenic Crystal NylonTM Frame
• Helps prevent Cataracts

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