Do I need a protective glasses? If yes which?

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begev79652
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Do I need a protective glasses? If yes which?

Thank you all for the help! I’ve ordered Convoy S2 5W and now I am thinking about the eye protection. Do I need it?

https://pubmed.ncbi.nlm.nih.gov/17469749/

“The purpose of this study was to evaluate the contribution of ultraviolet light (UV) as a causal factor of primary and pterygium recurrence. <…> UV light seems to have an important role in cause of primary and recurrent pterygium.”

Edited by: begev79652 on 06/17/2020 - 15:55
MNLegoBoy
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Yes, i recommend harbor freights uv blocking safety glasses

NeutralFan
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Yes it’s a good idea to wear eye protection when using a UV flashlight. Any polycarbonate safety glasses should work.

I have a Convoy S2+ UV flashlight and in the past not used eye protection and by accident shined it against something shiny. No eye damage, but I could feel it afterwards. It’s similar to wearing eye protection when working with power tools. You don’t expect anything to happen, but if it does, you’re glad you protected your eyes.

I’d rather use my flashlight around the house than turn on the lights.

Srgaudio
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Some level of protection is recommended, but even cheap polycarbonate safety glasses are pretty well sufficient for a 365nm led flashlight.

synerr
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Been looking for something similar, possibly with a bit higher protection in the 320-385 range.

Any recommendations for something reliably (and that also looks the part ) that’s available online from Europe?

B

High CRI or death!

fogofwar
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No you do not. Despite the “common wisdom,” UV exposure is minimal from a UV flashlight unless you look directly at the beam. It is analogous to worrying about the radiation exposure from eating a banana or from receiving a dental Xray.

You have to do the math and believe in the math.

Sunlight is 1400 watts per square meter. About 4% of sunlight which reaches the ground is UV so that is about 70 watts per every square meter during the day. In that case, 5 watts from your flashlight is negligible.

https://physics.stackexchange.com/questions/358117/how-much-light-does-t...

Henk4U2
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fogofwar wrote:
No you do not. Despite the “common wisdom,” UV exposure is minimal from a UV flashlight unless you look directly at the beam. It is analogous to worrying about the radiation exposure from eating a banana or from receiving a dental Xray.

You have to do the math and believe in the math.

Sunlight is 1400 watts per square meter. About 4% of sunlight which reaches the ground is UV so that is about 70 watts per every square meter during the day. In that case, 5 watts from your flashlight is negligible.

https://physics.stackexchange.com/questions/358117/how-much-light-does-t...

The math is simple, the reality is a different matter.
Have you ever tried to look prolonged into the sun? No you don’t.
And IF you did, your retina would be largely protected because you pupils constrict.
Just like the diafragm of a photocamera.

The snag is that your pupils react on visible light, and there is enough of that in the sun.
When using UV lights, people try to avoid the emission is visible light with ZWB2 filters.
So the light that comes out of your 365nm UV light is mostly (if not pure) UV light.
But your eyes can’t see UV light, your pupils stay open and the retina gets the full blast.
To keep it simple: you don’t see UV light, but the UV light sure sees you.

Ask any member with experience building their own lights.
Most, if not all, protect their eyes as good as possible.
Most of them feel some form of discomfort in their eyes after using a 365nm UV light.

And do keep in mind: this is not limited to looking directly into the light.
Try to avoid reflected light from mirrors, windows, and even shiny bathroom tiles.

You are a flashaholic if you are forced to come out of the closet, to make room for more flashlights.

Rayoui
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Srgaudio wrote:
Some level of protection is recommended, but even cheap polycarbonate safety glasses are pretty well sufficient for a 365nm led flashlight.

To add to this, you can easily test the effectiveness of any polycarbonate safety glasses at blocking UV. Just shine the UV flashlight through the lens of the glasses onto a piece of white paper. Most polycarbonate safety glasses will block 99.9% of UV.

When I use my UV lights in a dark room without safety glasses, it gives me a sensation like my eyes are physically straining, similar to focusing on an object that’s too close for a long time. Wearing safety glasses eliminates this.

fogofwar
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Henk4U2 wrote:
fogofwar wrote:
No you do not. Despite the “common wisdom,” UV exposure is minimal from a UV flashlight unless you look directly at the beam. It is analogous to worrying about the radiation exposure from eating a banana or from receiving a dental Xray.

You have to do the math and believe in the math.

Sunlight is 1400 watts per square meter. About 4% of sunlight which reaches the ground is UV so that is about 70 watts per every square meter during the day. In that case, 5 watts from your flashlight is negligible.

https://physics.stackexchange.com/questions/358117/how-much-light-does-t...

The math is simple, the reality is a different matter.
Have you ever tried to look prolonged into the sun? No you don’t.
And IF you did, your retina would be largely protected because you pupils constrict.
Just like the diafragm of a photocamera.

The snag is that your pupils react on visible light, and there is enough of that in the sun.
When using UV lights, people try to avoid the emission is visible light with ZWB2 filters.
So the light that comes out of your 365nm UV light is mostly (if not pure) UV light.
But your eyes can’t see UV light, your pupils stay open and the retina gets the full blast.
To keep it simple: you don’t see UV light, but the UV light sure sees you.

Ask any member with experience building their own lights.
Most, if not all, protect their eyes as good as possible.
Most of them feel some form of discomfort in their eyes after using a 365nm UV light.

And do keep in mind: this is not limited to looking directly into the light.
Try to avoid reflected light from mirrors, windows, and even shiny bathroom tiles.

Good point, however a fully dilated pupil is typically in about 6 millimeters in size, while a constricted pupil is about 3 mm. This is about a 4 times difference in area. I maintain that a UV flashlight is not dangerous unless there is prolonged exposure. Even incidental reflections are no more dangerous than reflections from sunlight.

Rayoui
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I wear eye protection in direct sunlight too.

fogofwar
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I’m not talking about direct sunlight. You would be looking a reflections from the UV flashlight. The amount of UV exposure is the relevant variable here and the exposure is significantly less than you would have in a sunny room without UV coated glass or looking out at sunny scene from the shade (even accounting for pupil dilation)

synerr
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Growing up in a hot country and having worked in North Africa for years I’ve always found sunglasses to be my friend.

To add some context to my question earlier I have a low powered UV emitter on my Nitecore Tiki. I showed the kids how some things ‘shine’ under UV and how my sunglasses block that and the halloween black light paint doesn’t get as excited when the light is behind the sunglasses even though they can still see the ‘violet’ pass through.

Now we were watching lots of videos of looking at rocks and minerals and stuff under UV and thought I’d use that as an excuse to get myself an S2+ UV and the kids a pair of good quality UV goggles for Christmas.

Regardless of how absolutely necessary the goggles are in this case I think that instilling good safety practices in children is a good thing.

High CRI or death!

Rayoui
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Indeed, better to err on the side of caution. UV LEDs may not be a powerful source, but the kind of damage they can cause to the eye is cumulative. Decent safety glasses are cheap. Might as well wear them if you’re going to be using the light for more than a few seconds.

djmcconn
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Synergy True that. You will never regret using good safety practices and instilling that in others. The opposite however may bite you. Even worse it may bite those you love. Let the foolhardy live with the consequences

Lightbringer
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fogofwar wrote:
Sunlight is 1400 watts per square meter. About 4% of sunlight which reaches the ground is UV so that is about 70 watts per every square meter during the day. In that case, 5 watts from your flashlight is negligible.

True, but in bright sunlight, your pupils contract to pinholes. In darkness and shining a UV light, your pupils are wide open.

I noticed getting “eyeaches” just from reflected UV when screwing around after a few minutes. Thought it may’ve been my imagination, ‘til others reported the same thing.

09 F9 11 02 9D 74 E3 5B D8 41 56 C5 63 56 88 C0

fogofwar
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Lightbringer wrote:
fogofwar wrote:
Sunlight is 1400 watts per square meter. About 4% of sunlight which reaches the ground is UV so that is about 70 watts per every square meter during the day. In that case, 5 watts from your flashlight is negligible.

True, but in bright sunlight, your pupils contract to pinholes. In darkness and shining a UV light, your pupils are wide open.

I noticed getting “eyeaches” just from reflected UV when screwing around after a few minutes. Thought it may’ve been my imagination, ‘til others reported the same thing.

“A fully dilated pupil is typically in the 4 to 8 millimeters in size, while a constricted pupil is in the 2 to 4 mm range. According to the American Academy of Ophthalmology, pupils generally range in size from 2 to 8 mm.”

A fully dilated pupil lets in at most 16 times more light with 4 times as more typical. You are exposed to hundreds of watts of UV light which a small linear portion is reflected back into your eyes on a sunny day. You get a similar fraction reflected back into your eyes from a UV flashlight but your source is 3-5 Watts instead of hundreds.

No one in this thread have shown my numbers to be off so the feelings can be attributed to the placebo effect which is stronger than you might think. Sure, you can buy polycarbonate glasses for peace of mind if you want. My point is that in the grand scheme of things, a UV flashlight is not dangerous. There are people who have worked in those laser tag places for years exposed to black lights.

kennybobby
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Happy Cataracts!

Your math assumes that the iris can block UV radiation—what makes you think that radiation doesn’t pass right thru? Just because you don’t see it doesn’t mean its not doing damage to your lens.

Now i used to think that i was cool,
drivin' around on fossil fuel,
until i saw what i was doin',
was drivin' down the road to ruin. --JT

mattlward
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My daily wear perscription glasses are poly lensed and also UV blocker treated, I can confirm with my basic testing that they block basically 100% of the output from my 365nm and 325nm lights. Basically shine light through them onto a reactive surface, mineral stone or paper, I get 0 reaction from either wave length.

EDC rotation:
KR4, SST-20 FA3 4000k (favorite!)
FW3A, Nichia 4000k sw40 r9080 (second favorite)
FW1A, LH351D 3500k (third favorite)
FW1A, XP-L Hi 3A
FW3A, LH351D 3500k
FW3A, SST20 FD2 4000k
FW3A, Cree XP-L Hi 5A3
Emisar D4V2, SST20 4000k
Emisar D4V2, brass E21A 3500k (night light of choice)

kennybobby
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What about UV-C at 254nm? None of the lights are monochromatic so the filter needs a wide bandwidth.

Now i used to think that i was cool,
drivin' around on fossil fuel,
until i saw what i was doin',
was drivin' down the road to ruin. --JT

mattlward
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All I can say is that they pass no illumination, I do not have that short a wave length source.

EDC rotation:
KR4, SST-20 FA3 4000k (favorite!)
FW3A, Nichia 4000k sw40 r9080 (second favorite)
FW1A, LH351D 3500k (third favorite)
FW1A, XP-L Hi 3A
FW3A, LH351D 3500k
FW3A, SST20 FD2 4000k
FW3A, Cree XP-L Hi 5A3
Emisar D4V2, SST20 4000k
Emisar D4V2, brass E21A 3500k (night light of choice)

wle
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most plastic eyeglass lenses are polycarbonate and block UV just fine for flashlight-levels

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