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Wolfenden
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Is there an experiment you can do at home to test whether a pair of sunglasses blocks UVA/UVB wavelengths? It says total UV protection but that could mean anything and I don't want wrinkles.
Welcome to the PF.Wolfenden said:and I don't want wrinkles.
berkeman said:Sunglasses aren't for preventing wrinkles...
The job of sunglasses is mainly to prevent cataracts and eye cancers, I think. Suncream can't do that and hats are only effective to some degree.alw34 said:that's the job of a [lotion] sunscreen or wide brimmed hat.
berkeman said:Welcome to the PF.
Sunglasses aren't for preventing wrinkles...
LOL, he was saying to use sunscreen to help prevent wrinkles...sophiecentaur said:Suncream can't do that and hats are only effective to some degree.
The point is they would only protect from wrinkles and sunburn in the small area around your eyes. They do not help where they cast no shadow (the rest of your face).Wolfenden said:They are if they claim to protect you from UVA light, UVB is what gives you sunburn :)
berkeman said:The point is they would only protect from wrinkles and sunburn in the small area around your eyes. They do not help where they cast no shadow (the rest of your face).
As the centaur says, the eyeglass protection is for different issues.
sophiecentaur said:The job of sunglasses is mainly to prevent cataracts and eye cancers, I think. Suncream can't do that and hats are only effective to some degree.
If you happen to have a pair of 'transitions' sunglasses, you could use them as indicators of the presence of UV.
But it's unlikely that you can do any valid experiment without the right equipment and the manufacturers are very shifty about giving any actual figures for performance. It seems that the 'UV400' standard is what's needed and that calls for 'total' blocking of all wavelengths below 400nm (whatever the word "total" means. I did a google search but I really couldn't recommend any particular link because they all seem to avoid putting in any actual figures and they're all from manufacturers. Funnily enough,I did find a source from eBay that seemed to say more than anything else I read.
Sorry I can't be more helpful but, even if the blocking is not complete, they are a lot lot better than nothing.Wolfenden said:I see, thanks.
sophiecentaur said:The job of sunglasses is mainly to prevent cataracts and eye cancers, I think. <snip>
I imagine you can use a black light to test whether UVA passes through enough to visibly detect the "best" protection of various glasses at least to some degree.Wolfenden said:Is there an experiment you can do at home to test whether a pair of sunglasses blocks UVA
Andy Resnick said:You raise an important issue, and the OP asks a good question. Sunglasses, because they reduce the amount of light entering your eye, result in a dilated pupil as compared to no sunglasses. Thus, dark sunglasses that don't effectively block UV light may actually lead to *increased* eye damage as compared to not wearing them. Same thing with ski goggles- if they darken the scene, your pupils dilate and more UV will enter your eye.
The same principle holds with laser safety- you are safer doing beam alignment, etc. with the room lights on.
One way to test the UV protection of sunglasses is to hold them up to a bright light source, such as a light bulb or the sun. Then, take a piece of paper or cardboard and place it behind the lenses. If the lenses are truly UV protected, you should not be able to see the light through the lenses.
Yes, you can test the polarization of sunglasses at home. One way to do this is to look at a bright, reflective surface (such as a mirror or a car windshield) through the sunglasses. Slowly tilt your head to the side. If the sunglasses are polarized, the glare should decrease or disappear as you tilt your head.
To check the fit of sunglasses at home, put them on and look in the mirror. The sunglasses should sit comfortably on your nose and ears without feeling too tight or too loose. You should also be able to move your head around without the sunglasses slipping or moving too much. Additionally, check to make sure the lenses are not too close or too far from your face.
One way to test the durability of sunglasses at home is to gently bend the frames and arms. If they are made of good quality materials, they should not bend or break easily. You can also try dropping the sunglasses from a low height onto a soft surface to see if they can withstand impact.
The best way to determine if the sunglasses have the correct tint for your needs is to wear them outside in different lighting conditions. For example, if you need sunglasses for driving, wear them while driving during the day and at night. If you need sunglasses for sports, wear them while playing the sport in different weather conditions. This will help you determine if the tint is suitable for your specific needs.