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13

Regular polarized sunglasses are usually meant for drivers of cars, as these glasses, in addition to darkening the sky, also suppress glare/reflections. If you travel in snow, light will come from all different angles and directions and will therefore be polarized in all kinds of directions, so a mere polarizer will not filter a sufficient amount of light. ...


12

Personally you don't need to go for any of the name-brands, unless that is important to you. Some things to look for: Comfort. Wear them for several minutes. Yes, the salesman is trying to wrap up this sale in under 2 minutes so he can get more commission. You will likely be wearing the shades for hours on end, so keep them on for at least a couple ...


10

Polarization and UV protection on sunglasses are two different things. While UV refers to light of a wavelength of approximately 10nm to 400nm, light of any wavelength can be polarized. Sunglasses with a polarization filter block light, that is horizontally polarized (e.g. light reflected on water). This has no specific effect on UV-light. So polarized ...


9

Polarized sunglasses, as with other type of sunglasses may not block enough UV to be considered safe. From WikiPedia: for adequate protection, experts recommend sunglasses that reflect or filter out 99-100% of UVA and UVB light, with wavelengths up to 400 nm. Sunglasses which meet this requirement are often labeled as "UV400. In other words, ...


9

The problem is that eyeglass prescriptions are calculated for a standard distance between the lens and the eye, with the lenses in flat frames parallel to the face. You can see the effect of varying lens-to-eye distance simply by pushing or pulling on your conventional eyeglasses, and the effect of angle by tilting them on the bridge of your nose. Your ...


9

Background Due to the very nature of light and lenses it is impossible to not have depth perception change when looking through a lens. The light will pass through the first surface of the lens, slow down (plastic is denser than air), hit the principle axis and then exit the second surface of the lens and converge at the focal point. What you are seeing ...


7

Those types of glasses do not provide adequate protection from sunlight, especially in areas with lots of reflective surfaces (desert, snow) and at high elevations where there's more UV radiation due to the thinner atmosphere above you. What you want are either wrap-around glasses which don't let light in the sides, or particular glasses called "glacier ...


7

Regular sunglasses should give you protection from snow blindness, so long as they protect against UV radiation. How well they protect you is dependent on how well the lenses cover your eyes, and how well the lenses or coatings filter or deflect UV radiation.


7

Various anti-fog products will work. I actually use the Rain-X anti-fog fluid (I had it for the car anyway and tried it successfully) You just need to clean the inside thoroughly, then apply it and it should last an entire season.


6

Ventilation is your friend. I hate to say it - but the glasses I've found that have this dialed are usually a little more expensive. After suffering through fog, wind sheer, and poor optics, I found a high end pair of glasses in the back-country, and my eyes were opened. As a second option, removing your glasses immediately when you stop (or even sliding ...


6

These are generally known as glacier glasses. They are rated as Category 4 on the CE scale and you aren't supposed to drive while wearing them. Sunglasses in Category 4 only transmit 4-8% of available visible light. Hidalogos sunglass guide has a very complete list of the different factors in choosing sunglasses. Category 4 come in a wider range of ...


4

When I first planned my trek in Himalays I was suggested to keep my Gogs and Glares with me when I am outdoor-bound, in snow. A good article in my Adventure related Database rtf files says: "Hours of bright sunlight can burn the surface of the eye, causing a temporary but painful condition known as Photokeratitis. Over time, unprotected exposure can ...


4

In Europe your will be hiking on altitudes less than 5000 m, and on these altitudes you can go with sunglasses without heavy specialized equipement. However not any piece of sunglasses will do. First, they have to be either made of glass (which stops UV rays) or special UV-proof plastic. Not every plastic stops UV rays, and if not, using it is even more ...


4

One of the classic applications of polarized sunglasses is to skiing. Light from the sun is unpolarized, but when it is reflected from a surface at a glancing angle, it becomes highly polarized. When you're on a snow field, a lot of the bright light getting into your eyes is light reflected from the snow, and when the sun is low in the sky, this glare is ...


3

Any sunglasses or will help protect against snow blindness. UV protection is highly recommended.


3

Paul and Kevin are correct here - any corrective lens has to alter what your eye sees. Your brain very rapidly corrects (a few minutes) but it is a basic function of optical physics that is unavoidable. It's not because of two layers of glass, it is the correction process - you are changing the light path. I would suggest that if you need the corrective ...


2

The basic idea of polarizing glasses is not to block all light, it's to block light that undergoes a glancing reflection, such as sunlight coming to your eye off of water or snow from near the horizon. The initially unpolarized light becomes highly polarized by this type of reflection, so by eliminating it, you make it easier to see and be comfortable ...


2

The sides on glacier glasses are invaluable when on a snowfield, as the sheer amount of light hitting your eyes is increased dramatically by the high reflection from the snow. Ordinary sunglasses allow a lot of light to hit your eye from all sides. I would recommend always using the sides when on snowfields.


2

I own only glacier glasses and use them as sunglasses as well (I take off the "blinders"). If you decide to go with sunglasses only, make sure they offer proper UV protection (not all of them do). Reasons as explained by @WedaPashi (I'd only add that while cataracts can be operated IMHO that is no reason not to try and avoid them).


2

Those large sun glasses that are used after cataract surgery are great - stops 100% of all types of uv and completely covers your eyes. New $70, used $5 at charity store or just take your mums. Yes, you will look like an old person and they are breakable plastic, but for $5, buy 2.


2

There are actual standards for this. If you are going somewhere where snow blindness is a real possibility, you should have sunglasses that meet the standard. The most common standard used in outdoor sunglasses is the Category standard based on the european CE standards. There are 5 categories 0-4 This page has a good overview. ...



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