| Author |
Message |
Greysky
Guest
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 Posted:
Sun Feb 06, 2005 8:40 am Post subject:
200 mw green laser - safe? |
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|
I have the opportunity to purchase a green laser with an output power of
150 - 200 milliwatts. How safe are lasers at this power level? Do I need to
get goggles to avoid burning out my retinas at this level, or are accidental
flashes still harmless?
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Scott Stephens
Guest
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| Posted:
Sun Feb 06, 2005 8:40 am Post subject:
Re: 200 mw green laser - safe? |
|
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Greysky wrote:
| Quote: | I have the opportunity to purchase a green laser with an output power of
150 - 200 milliwatts. How safe are lasers at this power level? Do I need to
get goggles to avoid burning out my retinas at this level, or are accidental
flashes still harmless?
|
Ask at alt.lasers and Mr. Goldwasser or Mr. Carlen will probably insist
you get goggles. I googled, but I can't get a link to the gov. specs,
and I'm not going to hunt it down fer you, unless you pay (=).
Use goggles, or un-collimate the damn beam!
--
**********************************
DIY Piezo-Gyro, PCB Drill Bot & More Soon!
http://home.comcast.net/~scottxs/
POLITICS, n.
A strife of interests masquerading as a contest of principles.
The conduct of public affairs for private advantage. - Ambrose Bierce
********************************** |
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artie
Guest
|
| Posted:
Sun Feb 06, 2005 8:40 am Post subject:
Re: 200 mw green laser - safe? |
|
|
In article <UBhNd.1446$lz5.1061@newssvr24.news.prodigy.net>, Greysky
<greyskynospam@sbcglobal.net> wrote:
| Quote: | I have the opportunity to purchase a green laser with an output power of
150 - 200 milliwatts. How safe are lasers at this power level? Do I need to
get goggles to avoid burning out my retinas at this level, or are accidental
flashes still harmless?
|
Appropriate warning sign:
WARNING - LASER - DO NOT LOOK INTO BEAM WITH REMAINING EYE
Anything over around 5mw can be a problem, even if not tightly
collimated or focused.
Please be careful!
--
Namaste--
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Dirk Bruere at Neopax
Guest
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| Posted:
Sun Feb 06, 2005 10:08 pm Post subject:
Re: 200 mw green laser - safe? |
|
|
Greysky wrote:
| Quote: | I have the opportunity to purchase a green laser with an output power of
150 - 200 milliwatts. How safe are lasers at this power level? Do I need to
get goggles to avoid burning out my retinas at this level, or are accidental
flashes still harmless?
|
Get goggles.
10mW is borderline for eye damage before blink reflex closes the eye.
200mW is seriously dangerous if you get a look at it.
--
Dirk
The Consensus:-
The political party for the new millenium
http://www.theconsensus.org |
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Mark Jones
Guest
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| Posted:
Sun Feb 06, 2005 11:48 pm Post subject:
Re: 200 mw green laser - safe? |
|
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Greysky wrote:
| Quote: | I have the opportunity to purchase a green laser with an output power of
150 - 200 milliwatts. How safe are lasers at this power level? Do I need to
get goggles to avoid burning out my retinas at this level, or are accidental
flashes still harmless?
|
Can I ask who your source is? I might be interested in one also.
-- "To deny our impulses... foolish; to revel in them, chaos." MCJ 200308 |
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Chris Carlen
Guest
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| Posted:
Mon Feb 07, 2005 7:29 am Post subject:
Re: 200 mw green laser - safe? |
|
|
Greysky wrote:
| Quote: | I have the opportunity to purchase a green laser with an output power of
150 - 200 milliwatts. How safe are lasers at this power level? Do I need to
get goggles to avoid burning out my retinas at this level, or are accidental
flashes still harmless?
|
Such a laser is a menace to humanity and will definitely blow a hole
clear through your retina.
You don't sound very experienced with these sorts of things. It might
be wise to experiment with a lower power laser for some time before
tinkering with something like this. You need to get a feel for how
laser light scatters off things, and reflects all over the place. Then
you can improve your chances of avoiding hazardous eye exposure.
To be honest, sometimes I am a bit too cavalier about lasers, which is a
consequence of handling them too much. To give you a clue about the
danger potential of that laser, I'll tell you a story.
A few months ago I got a simple 5mW green laser pointer (1/40 of the
power of the laser you are describing). Playing around with it
haphazardously, I somehow managed to get zapped straight in the eye with
it for a fraction of a second.
I have done this MANY times with <10mW HeNe (633nm red) lasers, and
never got hurt by them. Red light mostly diffuses across the retina and
so is much less dangerous than green.
The result was that as usual, there was a dot-shaped after-image in my
vision for quite some time. Usually, a several milliwatt laser zap
after-image will disappear in a few hours.
This one appeared to do so as well. But then a few days later, I
realized that when I had my glasses off, and I looked just slightly off
angle at points of light like a candle flame from a distance, I could
see a black dot surrounded by a very faint black ring (like an impact
crater) in the out of focus image.
I thought "oh shit, this time I really went and blew out a spot in my
retina."
What happened next was that I became somewhat obsessed with noticing
this spot. But it wasn't serious enough to appear as a persistent black
hole in my field of vision. Rather, it only would reveal itself with
some effort. Like I said, by looking at an out of focus point of light,
or by looking at the edge between two regions of very different brightness.
It also became distracting to my driving, as the obsession to determine
if the spot was obscuring my vision was actually the adverse distracting
consequence of the whole thing.
I became convinced that this was likely a permanent, though very tiny
spot of damage to my retina. I began to question whether I really
wanted to continue with the hobby of working with lasers. My job
entails working with lasers that are ridiculously dangerous, and because
of my general difficulties with maintaining concentration, I have been
seeking to work with them less and less over time as well as becoming
more and more diligent about following strict safety precautions.
But my home lasers which are "just" little CW green and red lasers, I
still tend to handle in a loose manner. I also hesitate to spend $150
on goggles. Though, the 150mW green laser that I possess (not the one
that dinged my eye) can be turned down to a very low power, and so can
actually be used more safely than a 5mW laser pointer.
Oddly, a few days later I discovered that the spot in my eye simply
vanished. I cannot find that black dot anymore. I really don't know if
it means that the damage was not permanent and the retinal receptors
recovered, or if there was permanent damage and the brain simply marked
that data as "bax pixels" and now interpolates over those receptors to
give the perception of an uninterrupted image.
The brain's signal processing is extremely sophisticated!
So the point, in summary, is this:
1. A laser over 5mW, particularly a green laser of 200mW, is definitely
dangerous.
2. You won't completely blind yourself in one flash if you look into
such a laser, as the eye focusses the beam into a tiny spot so that the
damage is actually restricted to only a very small area. But if you
were to sweep your vision at the same time as a 200mW laser beam entered
your eye, it is likely that the beam would sweep a line of damage across
your retina.
3. You should consider starting with a <=5mW laser, perhaps a red HeNe
or something, in order to get familiar with laser light and its
interactions with various types of reflective surfaces.
4. Do not point any laser at any person under any circumstances! I
would avoid pointing it out of a closed room at all, just to avoid any
sort of trouble, particularly as described below. Later, if you get
interested in the subject of laser shows after having developed some
experience and understanding, you can begin to make sensible judgements
about how to display lasers safely.
5. Whatever you do, DO NOT point that laser out the window into the sky
if there is any likelyhood of illuminating an aircraft. Actually just
don't point the thing outside at all. There is an increasing atmosphere
of paranoia and hype concerning the dangers of even small lasers to
aircraft. To be clear, these lasers ARE dangerous to aircraft, but not
to the degree that some of the news reports are making it sound. And
unfortunately, people are being subjected to the possibility of legal
consequences that may far outweigh the actual damage done in several
incidents.
Good day!
--
_____________________
Christopher R. Carlen
crobc@sbcglobal.net
SuSE 9.1 Linux 2.6.5 |
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Frank Bemelman
Guest
|
| Posted:
Mon Feb 07, 2005 8:41 am Post subject:
Re: 200 mw green laser - safe? |
|
|
"Chris Carlen" <crobc@BOGUSFIELD.sbcglobal.net> schreef in bericht
news:cu6g940f57@news2.newsguy.com...
| Quote: | Greysky wrote:
I have the opportunity to purchase a green laser with an output power
of
150 - 200 milliwatts. How safe are lasers at this power level? Do I need
to
get goggles to avoid burning out my retinas at this level, or are
accidental
flashes still harmless?
Such a laser is a menace to humanity and will definitely blow a hole
clear through your retina.
|
I know nothing about lasers, but would think that 200mW also
hurts/stings on normal skin, when hold still.
[snip]
--
Thanks, Frank.
(remove 'q' and 'invalid' when replying by email) |
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John Woodgate
Guest
|
| Posted:
Mon Feb 07, 2005 8:41 am Post subject:
Re: 200 mw green laser - safe? |
|
|
I read in sci.electronics.design that Chris Carlen <crobc@BOGUSFIELD.sbc
global.net> wrote (in <cu6g940f57@news2.newsguy.com>) about '200 mw
green laser - safe?', on Sun, 6 Feb 2005:
| Quote: | Oddly, a few days later I discovered that the spot in my eye simply
vanished. I cannot find that black dot anymore.
|
It was probably a 'floater', a blob of cells exuded into the vitreous
humour. I have lots of them in my left eye, due to a choroiditis about
40 years ago, and now I have a few in my right eye just due to anno
domini. Their visibility varies greatly from time to time.
| Quote: | I really don't know if
it means that the damage was not permanent and the retinal receptors
recovered, or if there was permanent damage and the brain simply marked
that data as "bax pixels" and now interpolates over those receptors to
give the perception of an uninterrupted image.
|
Such interpolation doesn't really happen, but damaged areas of retina
can be very difficult to detect. The damaged area in my left eye extends
from the periphery at about '4' to '5:30' on the clock face, inwards
about half way to the centre, but I can only see it by deliberately
looking for it with a specific object moved in my peripheral vision.
--
Regards, John Woodgate, OOO - Own Opinions Only.
The good news is that nothing is compulsory.
The bad news is that everything is prohibited.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk |
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Guest
|
| Posted:
Mon Feb 07, 2005 5:10 pm Post subject:
Re: 200 mw green laser - safe? |
|
|
Chris Carlen wrote:
| Quote: | Greysky wrote:
I have the opportunity to purchase a green laser with an output
power of
150 - 200 milliwatts. How safe are lasers at this power level? Do I
need to
get goggles to avoid burning out my retinas at this level, or are
accidental
flashes still harmless?
Such a laser is a menace to humanity and will definitely blow a hole
clear through your retina.
You don't sound very experienced with these sorts of things. It
might
be wise to experiment with a lower power laser for some time before
tinkering with something like this. You need to get a feel for how
laser light scatters off things, and reflects all over the place.
Then
you can improve your chances of avoiding hazardous eye exposure.
(...) |
Interesting post. I've got a similar story.
Well, once the green lasers came down in price, I
had to have one of them. I ordered a mod'ed laser pointer
guaranteed to be 5 mW (z-bolt.com - mod1). I already had an old (used)
He-Ne laser (~1 mW), and a couple of red laser pointers (all < 5 mW).
So I was already used to the behaviour of laser light - how it
relfects and interacts with most surfaces. I wasn't disappointed
with the greenie. I couldn't believe how bright it was. The
spot hurt my eyes to look at when I projected it on the wall a
couple of yards away. The laser would light up a dark room if
I projected the spot on the ceiling.
Well, I was playing around with the laser one night, standing
between two mirrors and bouncing the beam betweem them. I got
careless and took a direct hit in my right eye. Oof. Left quite
an after image, but I didn't think much of it at the time. My
vision seemed fine later. In the past I'd often caught direct
reflections from my red lasers. Never seemed to do any permanent
damage. HOWEVER, a couple of weeks later I started noticing this
little black spot, near the center of my vision. In my right eye,
near where the laser had hit. At first I noticed it when I first
woke up. Usually I'd only notice it when I'd blink, or when I would
quickly change what I was looking at. It would never appear all
the time (thank god), but I'd occasionally catch glimpses of it.
And no, it was not a floater. I've had floaters all my life -
I'm familiar with them. This spot was quite fixed.
It really, really, bugged me. It made me realize how precious
your vision is, and how fragile too. The eye was never designed
to deal with laser radiation - at least not a direct hit from the
beam. You know, the only sharp part of your vision is in the
very center of the retina - the macula. This tiny part of the
retina is about the size of a pinhead. If you were unfortunate
enough to damage it you might never see anything well out of that
eye again. Damage to the periphery of your vision can be
quite bad but still not be obvious.
The spot slowly seemed to fade. I agree with Chris - I don't
know if it actually healed, or if my brain is somehow compensating
for it. I saw an eye doctor recently, and told the doc what
happened. Doc gave me a thorough retinal exam, but could see
nothing wrong. Told me my retina looked fine. Doc also told
me that there are degrees of damage - apparently even low powered
lasers can cause subtle celluar damage that's not obvious
on an eye exam.
So... I still don't think these lasers should be banned, or
regulated differentlty than they are now. BUT, buyer beware.
Most of these lasers at worse can cause minor burns, but they
ARE very damaging to the old peepers. So be carefull, protect
your eyes and treat the laser with respect.
I shudder the thought of someone purchasing a 150 mW greenie
without having prior experience with lasers.
-Eric B |
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Mark Jones
Guest
|
| Posted:
Mon Feb 07, 2005 10:17 pm Post subject:
Re: 200 mw green laser - safe? |
|
|
boo@fractalfreak.com wrote:
| Quote: | Chris Carlen wrote:
Greysky wrote:
I have the opportunity to purchase a green laser with an output
power of
150 - 200 milliwatts. How safe are lasers at this power level? Do I
need to
get goggles to avoid burning out my retinas at this level, or are
accidental
flashes still harmless?
Such a laser is a menace to humanity and will definitely blow a hole
clear through your retina.
You don't sound very experienced with these sorts of things. It
might
be wise to experiment with a lower power laser for some time before
tinkering with something like this. You need to get a feel for how
laser light scatters off things, and reflects all over the place.
Then
you can improve your chances of avoiding hazardous eye exposure.
(...)
Interesting post. I've got a similar story.
Well, once the green lasers came down in price, I
had to have one of them. I ordered a mod'ed laser pointer
guaranteed to be 5 mW (z-bolt.com - mod1). I already had an old (used)
He-Ne laser (~1 mW), and a couple of red laser pointers (all < 5 mW).
So I was already used to the behaviour of laser light - how it
relfects and interacts with most surfaces. I wasn't disappointed
with the greenie. I couldn't believe how bright it was. The
spot hurt my eyes to look at when I projected it on the wall a
couple of yards away. The laser would light up a dark room if
I projected the spot on the ceiling.
Well, I was playing around with the laser one night, standing
between two mirrors and bouncing the beam betweem them. I got
careless and took a direct hit in my right eye. Oof. Left quite
an after image, but I didn't think much of it at the time. My
vision seemed fine later. In the past I'd often caught direct
reflections from my red lasers. Never seemed to do any permanent
damage. HOWEVER, a couple of weeks later I started noticing this
little black spot, near the center of my vision. In my right eye,
near where the laser had hit. At first I noticed it when I first
woke up. Usually I'd only notice it when I'd blink, or when I would
quickly change what I was looking at. It would never appear all
the time (thank god), but I'd occasionally catch glimpses of it.
And no, it was not a floater. I've had floaters all my life -
I'm familiar with them. This spot was quite fixed.
It really, really, bugged me. It made me realize how precious
your vision is, and how fragile too. The eye was never designed
to deal with laser radiation - at least not a direct hit from the
beam. You know, the only sharp part of your vision is in the
very center of the retina - the macula. This tiny part of the
retina is about the size of a pinhead. If you were unfortunate
enough to damage it you might never see anything well out of that
eye again. Damage to the periphery of your vision can be
quite bad but still not be obvious.
The spot slowly seemed to fade. I agree with Chris - I don't
know if it actually healed, or if my brain is somehow compensating
for it. I saw an eye doctor recently, and told the doc what
happened. Doc gave me a thorough retinal exam, but could see
nothing wrong. Told me my retina looked fine. Doc also told
me that there are degrees of damage - apparently even low powered
lasers can cause subtle celluar damage that's not obvious
on an eye exam.
So... I still don't think these lasers should be banned, or
regulated differentlty than they are now. BUT, buyer beware.
Most of these lasers at worse can cause minor burns, but they
ARE very damaging to the old peepers. So be carefull, protect
your eyes and treat the laser with respect.
I shudder the thought of someone purchasing a 150 mW greenie
without having prior experience with lasers.
-Eric B
|
Perhaps the inversion caused by the iris allows the laser light to "burn" part
of the macula in the center of the eye, producing a blackend line, which the
body slowly heals or it moves out of view? |
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Sam Goldwasser
Guest
|
| Posted:
Tue Feb 08, 2005 1:48 am Post subject:
Re: 200 mw green laser - safe? |
|
|
Mark Jones <abuse@127.0.0.1> writes:
| Quote: | boo@fractalfreak.com wrote:
Chris Carlen wrote:
Greysky wrote:
I have the opportunity to purchase a green laser with an output
power of
150 - 200 milliwatts. How safe are lasers at this power level? Do I
need to
get goggles to avoid burning out my retinas at this level, or are
accidental
flashes still harmless?
Such a laser is a menace to humanity and will definitely blow a hole
clear through your retina.
You don't sound very experienced with these sorts of things. It
might
be wise to experiment with a lower power laser for some time before
tinkering with something like this. You need to get a feel for how
laser light scatters off things, and reflects all over the place.
Then
you can improve your chances of avoiding hazardous eye exposure.
(...)
Interesting post. I've got a similar story.
Well, once the green lasers came down in price, I
had to have one of them. I ordered a mod'ed laser pointer
guaranteed to be 5 mW (z-bolt.com - mod1). I already had an old (used)
He-Ne laser (~1 mW), and a couple of red laser pointers (all < 5 mW).
So I was already used to the behaviour of laser light - how it
relfects and interacts with most surfaces. I wasn't disappointed
with the greenie. I couldn't believe how bright it was. The
spot hurt my eyes to look at when I projected it on the wall a
couple of yards away. The laser would light up a dark room if
I projected the spot on the ceiling.
Well, I was playing around with the laser one night, standing
between two mirrors and bouncing the beam betweem them. I got
careless and took a direct hit in my right eye. Oof. Left quite
an after image, but I didn't think much of it at the time. My
vision seemed fine later. In the past I'd often caught direct
reflections from my red lasers. Never seemed to do any permanent
damage. HOWEVER, a couple of weeks later I started noticing this
little black spot, near the center of my vision. In my right eye,
near where the laser had hit. At first I noticed it when I first
woke up. Usually I'd only notice it when I'd blink, or when I would
quickly change what I was looking at. It would never appear all
the time (thank god), but I'd occasionally catch glimpses of it.
And no, it was not a floater. I've had floaters all my life -
I'm familiar with them. This spot was quite fixed.
It really, really, bugged me. It made me realize how precious
your vision is, and how fragile too. The eye was never designed
to deal with laser radiation - at least not a direct hit from the
beam. You know, the only sharp part of your vision is in the
very center of the retina - the macula. This tiny part of the
retina is about the size of a pinhead. If you were unfortunate
enough to damage it you might never see anything well out of that
eye again. Damage to the periphery of your vision can be
quite bad but still not be obvious.
The spot slowly seemed to fade. I agree with Chris - I don't
know if it actually healed, or if my brain is somehow compensating
for it. I saw an eye doctor recently, and told the doc what
happened. Doc gave me a thorough retinal exam, but could see
nothing wrong. Told me my retina looked fine. Doc also told
me that there are degrees of damage - apparently even low powered
lasers can cause subtle celluar damage that's not obvious
on an eye exam.
So... I still don't think these lasers should be banned, or
regulated differentlty than they are now. BUT, buyer beware.
Most of these lasers at worse can cause minor burns, but they
ARE very damaging to the old peepers. So be carefull, protect
your eyes and treat the laser with respect.
I shudder the thought of someone purchasing a 150 mW greenie
without having prior experience with lasers.
-Eric B
Perhaps the inversion caused by the iris allows the laser light to "burn" part
of the macula in the center of the eye, producing a blackend line, which the
body slowly heals or it moves out of view?
|
Sorry, what are you trying to say? The damage from a visible collimated laser is
to the retina or its associated structures.
--- sam | Sci.Electronics.Repair FAQ Mirror: http://repairfaq.ece.drexel.edu/
Repair | Main Table of Contents: http://repairfaq.ece.drexel.edu/REPAIR/
+Lasers | Sam's Laser FAQ: http://repairfaq.ece.drexel.edu/sam/lasersam.htm
| Mirror Sites: http://repairfaq.ece.drexel.edu/REPAIR/F_mirror.html
Note: These links are hopefully temporary until we can sort out the excessive
traffic on Repairfaq.org.
Important: Anything sent to the email address in the message header above is
ignored unless my full name is included in the subject line. Or, you can
contact me via the Feedback Form in the FAQs. |
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redbelly
Guest
|
| Posted:
Tue Feb 08, 2005 3:49 am Post subject:
Re: 200 mw green laser - safe? |
|
|
boo@fractalfreak.com wrote:
| Quote: | The spot slowly seemed to fade. I agree with Chris - I don't
know if it actually healed, or if my brain is somehow compensating
for it. I saw an eye doctor recently, and told the doc what
happened. Doc gave me a thorough retinal exam, but could see
nothing wrong. Told me my retina looked fine. Doc also told
me that there are degrees of damage - apparently even low powered
lasers can cause subtle celluar damage that's not obvious
on an eye exam.
|
I suspect over time, the brain can compensate for permanent damage,
just as it does for the natural blind spot we are all born with.
I have had three separate jobs where I worked with lasers, and only at
one was a special eye exam required. It involved a preliminary exam
with retinal scan, at the beginning of my employment, to serve as a
comparison for any later tests for eye damage. Without that
preliminary scan, I don't know if small (but permanent) burns can be
detected.
Mark |
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|
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john cincotta
Guest
|
| Posted:
Tue Feb 08, 2005 6:17 am Post subject:
Sam Goldwasser |
|
|
Sam
I bought a hp 5501 laser over the weekend at a swap meet
it is a 1995 build date and looks different than the one
in the laser page. Id be willing to photo it and send them to you for
inclusion what size picts would you like horxvert pixels, kbytes
it was missing the front of the case (where the laser beam would come out.
I havent figured where to power it up yet. ive read the portion in the
laser faq 2x now and havent figuered it oout quite yet.
Good Luck
JOhn Cincotta |
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Sam Goldwasser
Guest
|
| Posted:
Tue Feb 08, 2005 6:51 am Post subject:
Re: Sam Goldwasser |
|
|
john cincotta <johncincotta@comcast.net> writes:
| Quote: | Sam
I bought a hp 5501 laser over the weekend at a swap meet
it is a 1995 build date and looks different than the one
in the laser page. Id be willing to photo it and send them to you for
inclusion what size picts would you like horxvert pixels, kbytes
|
I'd like to see the pics but no guarantees on including them.
800x600 .jpg is probably good enough.
| Quote: | it was missing the front of the case (where the laser beam would come out.
I havent figured where to power it up yet. ive read the portion in the
laser faq 2x now and havent figuered it oout quite yet.
|
If it has the 4 pin din connector, it's just a matter of applying +/-15 V,
and +5 V, and common to the appropriate pins. If you trace them to the
inside, it will be obvious. If not, I can get you the pin designations.
Once power is applied (with the cover in place so the interlock is activated),
the laser tube should come on in a few seconds, and if the rest of the
electronics is operational, the "Locked" LED should come on in a minute or
so.
How much different is it than the one in the Laser FAQ?
I assume you mean these pics:
http://repairfaq.ece.drexel.edu/sam/laserpic/henepics.htm#henetoc
under "Hewlett Packard 5501 Helium-Neon Laser".
http://repairfaq.ece.drexel.edu/sam/laserpic/henepics.htm#henehph
Thanks.
--- sam | Sci.Electronics.Repair FAQ Mirror: http://repairfaq.ece.drexel.edu/
Repair | Main Table of Contents: http://repairfaq.ece.drexel.edu/REPAIR/
+Lasers | Sam's Laser FAQ: http://repairfaq.ece.drexel.edu/sam/lasersam.htm
| Mirror Sites: http://repairfaq.ece.drexel.edu/REPAIR/F_mirror.html
Note: These links are hopefully temporary until we can sort out the excessive
traffic on Repairfaq.org.
Important: Anything sent to the email address in the message header above is
ignored unless my full name is included in the subject line. Or, you can
contact me via the Feedback Form in the FAQs. |
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|
Mark Jones
Guest
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| Posted:
Tue Feb 08, 2005 8:40 am Post subject:
Re: Eyeball Damage - 200 mw green laser - safe? |
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Sam Goldwasser wrote:
| Quote: | Mark Jones <abuse@127.0.0.1> writes:
Perhaps the inversion caused by the iris allows the laser light to "burn" part
of the macula in the center of the eye, producing a blackend line, which the
body slowly heals or it moves out of view?
Sorry, what are you trying to say? The damage from a visible collimated laser is
to the retina or its associated structures.
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Well the eye is not hollow, it has some kind of goo in the center, which is not
just a clear liquid. Look at an eyeball in long-wave UV light - the inside will
glow. A family member has a macular hole in this substance, severely affecting
vision. Anyways, perhaps the iris focuses this "not too terribly bright" light
enough to BURN the goo inside the eye, leaving a thin black line going from iris
to retina. Slowly, over time, the damage is repaired.
I'm not sure if this is possible or not, just throwing out ideas. We do
understand that the lens doesn't focus all the light energy directly onto the
retina, right? There is some image-flipping going on there about 2/3rds the way
to the retina. That tightly-focussed area is where I'm talking about. The light
intensity-per-mil would be many times greater than "5mw."
ISTR that the cones in the retina are far more sensitive to green wavelengths
however as a result of our evolution in distinguishing prey in green (leafy)
environments. So it might be simple retina damage, dunno.
-- "If a cluttered desk is the sign of a cluttered mind, what is the
significance of a clean desk?" -- Laurence Peter |
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