CON-SUB UV Harmful to human eyes/vision(?)

MrSpectrum

Gray-bearded Member
Sorry if I'm beating a dead lizard here--I tried the search facility and Google, but didn't find anything close to what I was looking for.

FIRST, I'm still garnering information--I haven't reached any personal conclusions yet.
SECOND, I'm not/don't mean to be proselytizing--just passing along what I was told by a professional.

I recently had an eye exam. My optometrist likes to keep things casual by chit-chat, which is fine.
The topic of getting/keeping a BD came up, as did the UVB requirement. He cautioned me that UV is/can be harmful to human eyes/vision, especially if/when the bulb is viewed directly. I asked if it was just one type (UV-A or UV-B) and he said any UV. This went into my decision to mount the UV-B tube above the false ceiling in the enclosure I'm building, and if necessary, add a shade/barrier that would prevent anyone looking into the enclosure from being able to see the bulb directly. I'm also wondering if this might only be a problem if a viewer was within the effective range of the bulb (though again, in my case, a viewer would be within effective range).

Has this been discussed here? Anyone have a link or links to pertinent discussions/articles?

Thanks.
 

kingofnobbys

BD.org Sicko
True UV is harmful to human eyes , so best to avoid staring straight into your UV sources.

Note that if the source is behind glass (as in a reptile tank) UVB is blocked by common glass. UVA is transmitted quite well ( about 80% is passed )..

transmission-of-glass.png

Ref SHIMADZU Scientific Instruments Corp UV-3600 UV-VIS-NIR Spectrophotometer Manual
 

Claudiusx

BD.org Sicko
Staff member
Moderator
UV can be harmful to all creatures, not just humans. That's why I'm so against the mindset of "more is better" or "the strongest bulbs with the strongest reflectors are best"

But I digress

To answer your question, glass blocks the majority if not all uvb radiation. You could stare at it through the glass in your tank if you wanted. The only strain on your eyes would be the luminosity of the bulb, the same as if you stared into a flashlight. Unless you were close enough to the bulb (eg face pressed against the glass to to receive the uva dose)
Additionally, the uv bulbs we have available in our hobby are no where near the power or strength of the sun. Sure we can use them to mimic and surpass uvi and mW uv2 levels. But what I mean is that these bulbs outputs drop significantly with distance. And you know this based on all the research you've done :)

Sure, I make a point of not directly exposing my eyes to the bulb unobstructed, but it's not a concern under normal... "operating conditions." Lol.

To coat tail off of that, that's also why it's important that the bulb be mounted overhead the dragon, and not horizontally along the side or wall of the enclosure.
Furthermore, there is possibly some importance to having another bright light source (either a basking bulb or supplemental full spectrum lighting) for purposes of dilation of the pupils.

-Brandon
 

MrSpectrum

Gray-bearded Member
Original Poster
Thanks guys,

The way I read you, I don't think I'll be changing anything I mentioned. While the glass will be closed most of the time, there's always the instinct to look/go toward the light, whether myself or unaware guests if/when the glass happens to be open.

Nice chart Kingofnobbys, but I'm not enough of a geek to interpret it completely yet (except guessing that the vertical axis is the percentage of whatever is passing through those substances).
But percentages of what passing through? UV? White light? Sunlight?
 

Claudiusx

BD.org Sicko
Staff member
Moderator
MrSpectrum":2z2wckkn said:
While the glass will be closed most of the time, there's always the instinct to look/go toward the light, whether myself or unaware guests if/when the glass happens to be open.
It's something to be aware of, but not a huge concern imo. Naturally your eyes would be screaming at you to look away if you did look into something that they didnt like. That's why you can stare at the bulb from a distance, but as you get closer it becomes harder and harder to do.

But it's an interesting topic to discuss none the less :)

-Brandon
 

Claudiusx

BD.org Sicko
Staff member
Moderator
Additionally, plexiglass (if you were to use that instead of glass) seems to block out uv up to around 300nm in size. Which is up in the uva range.

-Brandon
 

kingofnobbys

BD.org Sicko
MrSpectrum":u7w3cdf5 said:
Thanks guys,

The way I read you, I don't think I'll be changing anything I mentioned. While the glass will be closed most of the time, there's always the instinct to look/go toward the light, whether myself or unaware guests if/when the glass happens to be open.

Nice chart Kingofnobbys, but I'm not enough of a geek to interpret it completely yet (except guessing that the vertical axis is the percentage of whatever is passing through those substances).
But percentages of what passing through? UV? White light? Sunlight?

% of the EMF radiation (UV or visible light or near IR) at the wavelength that is transmitted through the "glass".
 

kingofnobbys

BD.org Sicko
claudiusx":jbryf9ik said:
Additionally, plexiglass (if you were to use that instead of glass) seems to block out uv up to around 300nm in size. Which is up in the uva range.

-Brandon

Actual spectral transmission of Plexiglass and other common plastic sheets (and films) is shown below:
transmission-of-different-grades-of-plexiglass.png

ref Ridout Plastics Tech Specs
Grades UF-3 , UF-4 and UF-5 are the grades of Plexiglass that will act as effect UV cutoff filters.

transmission-of-plastics-1.png

PVF is effective at blocking UV.

transmission-of-plastics-2.png

ref Perry's Chemical Engineers' Handbook

Any good safety gear shop will stock UV blocking safety glasses , these are relatively cheap and very easy to find.
 

MrSpectrum

Gray-bearded Member
Original Poster
kingofnobbys":3g7duruo said:
Any good safety gear shop will stock UV blocking safety glasses , these are relatively cheap and very easy to find.
For us or the 'zards? :mrgreen:

And how did this thread drift from an (intended) PSA to... (Imagine Lou Costello saying this:) I DON'T EVEN KNOW WHAT YOU'RE TALKIN' ABOUT! :shock:

I do speak/understand some nerdese--just not this particular dialect... :oops: :lol:
 

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