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Temporary blinding of a human with light


Bio-Hazard

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You do start some lovely threads, don't you?

 

Flash blindness is quite common. It can last from a few seconds to forever. Have a dig around for laser safety thresholds, flash pump powers, etc. and try to work it out. It's very subjective, though, since not many people will say "Sure, flash me, and we will see"!

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  • 4 months later...

Dangerous, I played with L.A.S.E.R.s in middle school. Unfortunatly I never played with the flash-lamp Ruby version, just electricly He-Ne tubes so i never had a chance to experience the 'joys' of being blinded by unsheilded flash-lamps.

 

I can say that your eyes should be protected at all costs when you do play with them.

 

The closest thing to ligh blindness I've experienced was from looking into a 100W lightbulb while I was changing it's mate in a dual-socket fixture, had a spot in my vision that was kinda blue kinda black for about an hour afterwards. Now that was disorienting.

 

Either way, guard your peepers and don't go out trying to blind yourself; you might be too sucessful if you know what I mean.

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I always wondered about those wierd black spots. Sometimes I get them when I look at the sun.. Anyone knows what they are?

Yeah - a temporarily fried retina.

 

Your lenses are quite efficient at focusing the image onto your retina, so when you stare at the sun, you physically fry your eyeball. Or a tiny spot on your retina wall, at least. Staring at the sun long enough, will indeed cause a permanent blind spot.

 

Used to do it as a kid, only cause my mom said it was a bad idea. Turns out she was right.

 

Kids - LISTEN TO YOUR MOTHERS!

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Except your eyeball has fluid in it that will dissapate the heat somewhat.

Yeah - a viscuous translucent snot that lets light pass through quite efficiently; else you won't see nuttin'.

 

If you take a magnifying glass and hold it over some water, nothing would happen, because it lets light through. Put something that'll stop the light at the point of concentration, and the sucker'll still fry. Kinda like your retina.

 

Therefore, like momma use to say, 'JESUS CHRIST! I done tol' y'all a million times, don't stare into the son, you bastard!'

 

PS - I thought my name was Jesus Christ till I was about seven.

PPS - She could never explain the 'bastard' bit, either.

PPPS - Good thing she never called me a 'son of a *****', though.

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Yeah - a viscuous translucent snot that lets light pass through quite efficiently; else you won't see nuttin'.

 

If you take a magnifying glass and hold it over some water, nothing would happen, because it lets light through. Put something that'll stop the light at the point of concentration, and the sucker'll still fry. Kinda like your retina.

No, what I meant is that the fluid in the eye would conduct heat away from the focus point of the light a lot better than air would. That wouldn't save your eye, but it would be better than if the eye was filled with air.

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No, what I meant is that the fluid in the eye would conduct heat away from the focus point of the light a lot better than air would. That wouldn't save your eye, but it would be better than if the eye was filled with air.

It buys you a little time. So you go blind slower. Unless you are fond of service dogs and braille, don't look at the sun.

 

Bill

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*** SIDEBAR ***

 

Shouldn't blind people have their fingers 'tested' every now and then?

And if they do, where do they go for that?

Do they get rated like '20/20 on the index finger, but only 15/20 on the thumb'?

And if they have guide dogs, shouldn't the dogs eyes get tested every now and then, seeing as they walk through traffic 'n stuff?

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The "white" of the eye is much like the white of an egg. You *really* don't want to cook it. Staring at the sun won't do that, though, not on a normal day at sea level, unless you recently moved to the equator. Yes, it is painfully bright, but you are unlikely to become permantly blind from it. Evolution, and all that...

 

Having spent many hours staring into ~10mW of red laser, and having dazzled myself with ~5-50mW of green many times, I can safely say you are unlikely to go blind from that either, unless you really do something stupid.

 

As for the sense of touch, brain scanning has shown that, much like the map area of taxi drivers brains, the sense of touch for a blind person becomes much more refined. (The same is alledgely true for safe crackers!) The ears also become more sensitive, and during WWI, the UK forces used large funnels, focusing walls and blind people to detect the launches of rockets from France, a distance of some 35 miles!

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