I bought this UV light (just received it). Do I need to wear eye protection while using it? Or is it just the simple "don't look directly into the light"?
Thanks,
Garry
Really 375nm? Actually, I kind of doubt it, but it should still be cool. My thought (Entirely uneducated, and based on my limited understanding of the capabilities of budget UV LEDs and how UV works, YMMV):
You should be fine if you don't look directly into the light for extended periods. That said, a $5 pair of UV-protecting glasses will definitely result in reduced eye-strain while using the light. And of course, the same $5 pair of UV-protecting glasses with yellow/amber lenses will really allow you to see more fluorescence. Cool things like leaves that fluoresce deep red and tiny mushrooms that faintly glow under the blacklight, but are washed out by the visible blue...
My local Wal Mart has some surprisingly good UV-protecting safety glasses with tinted, clear, or yellow lenses for $4.97/pair. I use a pair with the yellow lenses with my UV light and they work great. The UV blocking is legitimate; shine your UV light through the lens onto a highly fluorescent object and it will not glow. The glasses (in my store) are hanging near the ends of aisles around the sporting goods section in a cardboard display unit about 18"x24" IIRC. Get the wrap-around model if you can find them; they breathe better than the ones with frames...
I always felt that shining around the UV flashlight in my flat is kind of stressful for my eyes. I don't have that feeling with eye protection, so I'd definitely recommend it.
Besides, you'll see much more if you wear these yellow UV protection glasses, it's a difference like night and day.
Alright guys, thanks! I'll try to swing by Walmart for the $5 pair of yellow ones soon.
-Garry
Using longwave UV without eye protection = supposedly okay. Using shortwave UV without protection = not okay.
Glass interferes with UV light, especially shortwave UV (the harmful stuff).
“Ordinary glass is partially transparent to UVA but is opaque to shorter wavelengths, whereas silica or quartz glass, depending on quality, can be transparent even to vacuum UV wavelengths. Ordinary window glass passes about 90% of the light above 350 nm, but blocks over 90% of the light below 300 nm.[12][13][14]”
That’s what the guys told me when I used to work at GIA, the gem ID company.
Of course, many plastic prescription glasses and sunglasses are also coated so UV rays won’t pass through. But wearing sunglasses at night while hunting scorpions with a UV light may look cool but you couldn’t see what you were doing. 
Having said this, I always think about where these emitters come from — China. How do we know that they really are COMPLETELY long-wave? I sure don’t. I have no way of testing them. They could be half short-wave or closer to the short-wave spectrum.
We know that they are primarily long-wave because long-wave sensitive objects glow as they should. But I don’t know enough about UV emitters to know if it’s possible to have short-wave (dangerous) UV radiation mixed in with the safe long-wave UV light. I’m sure — like most of the overseas stuff we get on this forum — if the overseas manufacturer can make it cheaper with partial short-wave, that’s what they’ll do. Couple hundred blind, sterile customers? Not a problem.
THEORETICALLY, most of the shortwave UV radiation should be stripped out by the flashlight’s glass lens?
But I still wear glasses.
+1 Plus, how are the customers going to first notice they are going blind because of an intermittently used (and probably rarely used) UV flashlight, and the Chinese companies dont have to abide by our laws, would be difficult to sue and probably have some vague warning anyways to cover their butts. And maybe they figured out using a cheap plastic “glass” that doesnt block shortwave UV is cheaper…I’d use glasses all the time if I were you. Also I wouldnt use it for long periods or shine it on your skin for the same reasons…
You guys have valid points. Thanks! Going to also teach my daughter that this light is not a toy (nor will I leave it out where she can get a hold of it).
-Garry