Polarized sunglasses, as with other type of sunglasses may not block enough UV to be considered safe.
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
In other words, you ...
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 ...
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 ...
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 at ...
According to article Benefits of Copper, Orange, Yellow And Brown Lens Tints and from my own experience, but with cycling solar glasses:
Copper, orange, yellow/amber and brown lens tints make an environment appear brighter and are commonly used in low-light conditions. These lens tints significantly block blue light and enhance contrast and depth ...
A clean sock will protect them from scratches with no need for fasteners and it takes a fair bit of pressure or impact to actually damage glasses (bending them slightly is another matter). Once wrapped they can go in the top of your pack or any pocket.
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 ...
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 ...
I'm an extremely nearsighted person who has trouble with contacts and spends a whole lot of time being active outdoors. As a result, I've done a lot of investigating into prescription sunglasses, and tested several pairs.
The biggest difference between sunglasses and regular glasses is that sunglasses need to block out a larger area than a regular glasses ...
I like the idea of glasses that change from sunglasses to indoor
Photochromic lenses are a lot less useful than most people think when they hear about the concept. The main problem is that the change takes time - about a minute to darken and nearly five minutes to un-darken. That makes them basically useless for things like tunnels. Another problem is that ...
For the scenario, no backpack, no nothing, just a short hike and you find your treasure shining in the sun.
Find a piece of grass that won't break easily and can be bended without breaking in segments
Put one arm of the glasses through a belt loophole on your jeans.
close the glasses
Wrap the grass over the arms of the glasses to prevent them opening up and ...
Blue light can injure the eyes.
Is there any reason to avoid blue lenses? Will I do more long-term damage to my eyes than choosing another option like these?
UV light (which is blocked by good sunglasses) can cause photo ceratitis and conjunctivitis (inflammation of the cornea and/or the conjunctiva), but it doesn't penetrate deeply into the human eye as ...
Blue may be somewhat more likely to let UV through if they are poor quality. Most sunglasses now carry some form of label regarding UV blocking.
In photography, you often use an orange or red filter to increase the effective contrast between sky and cloud, or rock and vegetation. These filters also reduce the effect of haze, which is biased toward the ...
This did indeed happen to Robert Swan, who is the first man in history to walk to both the South and North Poles. His eyes turned from dark blue to light blue on his trek to the South Pole, which began in November of 1985 and ended at the Pole in January of 1986. (His trip to the North Pole was in 1989.)
There are very credible sources, but the best one is ...
Safety glasses would presumably meet some safety standard, for example impact resistance, and the standard so meet would be cited.
Shooting glasses might offer some impact resistance (or other protection...), but wouldn't have to meet the standard.
Any sturdy box big enough to hold them would work, also when the box is a lot bigger.
You can fill the empty space with something soft, like a piece of clothing you happen to have handy.
The smaller (but still big enough) your box is, the more snug your pair of glasses will sit.
In a sturdy box you can put your glasses in any kind of bag.
When you do not ...
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:
An Explication of ...
I won't discuss the aspects that the other two answers have covered well.
I am very near-sighted. For my non-sunglasses, I have what are called "progressives". I think this is what you are calling bi-focal, multi-focal. For my sunglasses, I skipped the progressive feature, which I don't find very useful anyway. Outdoors, I am focused on distance almost ...
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 ...
The dark tint isn't required for UV blocking. That's not to say it's not a good thing to have.
Many plastics have strong UV absorption, and some safety glasses have an additional coating.
For blocking UV lasers this has been tested, though UV laser glasses are often a pale straw colour. Many safety glasses actually have UV protection anyway.
There are ...
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.
"blinkers"/blinders (usually leather or plasic pieces that close the gaps at the side and top of sunglasses) effectively block diffuse, ambient, scattered and reflected light coming from the side (of all wavelengths).
For the UV protection of the lens, check the description of the sunglass. Or measure/have measured the UV transmission spectrum.
There is no ...
For my diver mask and mask for skiing I'm using following trick(should also work with glasses):
Clean your mask\glasses as much as possible(inner part of lenses of
course). For cleaning I'm using normal toothpaste.
mask\glasses clean and never touch it with your fingers.
There are some great answers here that helped me make my decision. Making the final decision becomes personal choice. There are several options, with some more heavily weighted to certain needs.
Can or do you wear contacts lenses?
Consider using non-prescription sunglasses with your prescription contacts.
Is the cost of new prescription lenses is a ...
Blocking UV and reducing visible light intensity are separate functions, and the latter can actually reduce the former; glasses that are opaque to UV but completely transparent to visible light will mean that pupils will be constricted in direct sunlight, reducing UV exposure.