Frequently Asked Questions
We noticed that there are certain questions about sunglasses and sunglass trading, that get asked very frequently. Why stay in doubt or dark? Check out the following – may be your question has been answered already!
1. If the sun doesn't bother your eyes, do I still need to wear sunglasses?
Yes. Even when the sun does not shine bright, the damaging UV rays are still there. These UV rays can cause photokeratitis, pingueculae, and permanent retinal damage.
2. What exactly are UV rays? How does it affect the eyes?
Ultraviolet (UV) rays are located just past the violet portion of the visible light spectrum;UV light is broken into three different types: UVA, UVB and UVC. UVA has longer wavelengths and passes through glass easily; among these UVB rays are the most dangerous, making sunglasses and sunscreen a must; they don't go through glass. UVC rays do not reach the Earth because its atmosphere blocks them. But UVB rays can even damage the eyes completely and wide exposure of the eyes to this without sunglasses is truly harmful.
3. When do UV rays affect my eyes?
The UV rays are likely to be very much effective from 10 am to 2pm when sun's rays are the strongest. UV rays are there even when the sky is overcast with clouds and the weather is not sunny.
Glare and reflections can create trouble, so have your sunglasses ready if you'll be around snow, water or sand, or if you'll be driving (windshields are a big glare source).
4. Can certain medical problems increase my risk for damage from UV rays?
Yes of course. People with diseases like cataracts (or who've had cataract surgery), macular degeneration, and retinal dystrophy should be extra careful. Because exposure to the eyes without glasses can cause damage thereby leading to permanent blindness.
5. What are the best options to prevent damage to my eyes?
Well, in this case the best option is to cover your eyes with a pair of sunglasses. Although some contact lenses provide UV protection, they don't cover your whole eye, so you still need sunglasses.
Look for sunglasses that protect you from 99 percent to 100 percent of both UVA and UVB light. This includes those labeled as "UV 400," which blocks all light rays with wavelengths up to 400 nanometers. (This covers all of the UVA and UVB rays.). You can also go for a wrap around sunglass to prevent harmful UV rays from entering around the frame.
6. What are the different kinds of lenses that are available? Which one is best for eye protection?
Well, this is indeed very difficult. You are likely to be confused with so many lenses available in the market. Therefore you should know the purpose of different lenses, and then you will know, which one is suitable for you.
Blue-blockers block blue light and usually have amber lenses. Researchers are still unsure whether or not blue light is harmful, but these are popular among skiers, hunters, boaters, and pilots.
Both polarized lenses and anti-reflective coating cut reflected glare. Polarized lenses in particular are popular with those who play water and snow sports.
Mirror-coated lenses limit the amount of light entering your eyes, so you're more comfortable.
Gradient lenses are tinted from the top down, so that the top of the lens is darkest; they're good for driving. Double gradient refers to lenses that are also tinted from the bottom up: the top and bottom are darkest and the middle is clear (or close to it); double gradients are not very useful for driving, because they make it difficult to see the dashboard.
Photochromic lenses adjust their level of darkness based on the amount of UV light they're exposed to.
7. What about sunglasses blocking infrared rays?
Infrared rays are located just past the red portion of the visible light spectrum. While some experts believe that infrared light can be harmful in certain situations (near large bodies of water or at high altitudes), most feel that the sun's infrared rays do not pose a danger to the eyes.
8. Which lens color is the best?
Color is a personal choice and doesn't affect how well the lenses protect your eyes from UV light. Gray and brown are mostly popular because they distort colors the least. Athletes may choose other tints for their color-enhancing properties; for example, yellow lenses are popular with skiers and target shooters because they work well in low light, reduce haze, and increase contrast for a sharper image.
9. Do I still need those "UV Protective" sunglasses if my lenses are real dark?
Yes of course. Most people think if the lenses are dark it protects their eyes. But the actual fact is that the degree of darkness has no effect on UV rays. For adequate protection, you need to buy sunglasses that indicate they block 100 percent of the sun's UV rays. The color of the glasses does not affect the UV protection of the lens.
10. Are the more expensive sunglasses of better quality?
Not necessarily. While expensive sunglasses are usually high quality, you can also get a good pair for under $20 if you're a careful shopper. Just make sure to check that they provide adequate protection from UV light and are free of distortions.
11. Children don't need sunglasses, do they?
Children are at particular risk because they're in the sun much more than adults. Their eyes are more sensitive also. UV rays therefore affect a child's eyes all the more and can even damage them completely leading to permanent blindness. Sunglasses are must to protect the child's eyes.
12. Do those sunglasses for specific sports really make a difference?
Yes they do. Sports eyewear in general tends to be safer than regular sunglasses. Since the sport sunglass lenses and frames are made of special materials they are unlikely to shatter if struck and can give you the benefits of both sunglasses and protective eye wear. But it is also true that certain lens colors can enhance your vision for certain sports. Brown, for example, is popular with golfers because it provides nice contrast with the green golf courses.
13. Why polarized glasses are more acclaimed than ordinary sunglasses?
The obvious answer to this question is polarized glasses reduce glare. Polarized sunglasses lenses are truly useful in high-glare situations, such as driving, boating, golfing, surfing, and fishing. The polarized lenses help reduce glare, which can be a real problem in water sports and many other outdoor activities. Ordinary sunglasses cannot cope with the bright glare. Choose polarized lenses if you have to stay outside in the high-glare situations.
14. Aren't polarized sunglasses expensive?
Polarized glasses today are not that expensive. You can get polarized sunglasses starting at $9.99.
15. How can you distinguish the polarized lens?
A polarized lens filters scattered and reflected light. If you look at water with a standard lens, the surface of the water will be reflecting light from all different directions so it's difficult to clearly see an object under water. Polarizing the light filters those reflected rays so you can see below the surface of the water clearly.
16. Are those polarized glasses really polarized?
Most new polarized sunglasses should come with a lens sticker indicating they are polarized. The test tag is used by wearing the glasses and looking through the lens material embedded in the tag while rotating the tag 90 degrees. At a certain point the material in the test tag should become noticeably darker. In case you have no test tag you can take two pair of polarized glasses and look through both, now rotate one glass 90 degrees. You should see an obvious blocking of light if both glasses are polarized.
17. What is the significance of 1.1mm vs .75mm polarized glasses?
.75mm polarized lenses are made from thin sheets of film and are used in glasses where impact resistance is not required.
1.1mm polarized lenses are made from thicker sheets of film. But in spite of that the polarizing layer is the same thickness as the .75mm film. 1.1mm of polarized lens is thicker to offer impact resistance. Generally 1.1mm lenses are more expensive but they do not offer more "polarization" nor will they reduce glare any better than .75mm lenses.
Most of the sunglass users go for .75 mm polarized lens.
18. What is the basic difference between the anti-reflective and the polarized lenses?
Anti-reflective lenses actually cuts out most of the reflections produced by the light and rebounds between the two lens surfaces. This obstructs in proper vision. But the polarized glasses rejects light completely from the horizontal meridian thereby reduces the glare.
19. How many kinds of sunglass frames are there?
Sunglasses frames are made mostly of three materials-plastic, nylon and metal.
Plastic is mostly found in the less expensive sunglasses. If you like plastic frames, then choose plastic reinforced with a metal rod or otherwise the plastic frame may crack easily.
Nylon frame is always a good choice because it is flexible, light and strong with a tendency to return to its original position.
Metal is also a good choice because of the strength. The main drawback of the metal frame is that they will bend and break more easily than nylon.
20. How to choose a suitable sunglass frame?
Well, choosing the appropriate sunglass frames is truly difficult. Before choosing them, keep the shape of face and head in mind.
Those with round shaped glasses look for the narrow models that are sleek. Rectangular shapes look the best because they lengthen rounder faces and make them appear thinner.
If you have oval face you can wear almost any sunglass style. The only style you need to stay away from is the cat’s eye models or models that angle upwards.
If your face is square shaped, choose sunglasses styles with soft lines, which balances the edgy curves of your face.
