retina damage from infrared laser :(

Hello

three days ago, at my work, i had to install a free space optic
transceiver for some customer , its an infrared laser, around
830-860nm at 16mW power, class 1m, its used to connect two computer
networks between buildings. Both tranceivers have a telescopes
built in what are used to align both heads to point at each other.
Anyway, i was looking through that telescope while both tranceivers
where on, so laser beam was entering my eye through a telescope, and
an eye contacts , what i was wearing at that time. I was only looking
through my right eye tho.

Anwyay, the result is that now i feel a pain at the back of my right
eye, like a needle picking inside my eye, and my vision is worse
then the left eye. Also, that dark dot (pupil?) is bigger then in
the left eye. I thought that maybe it would go away after a little
while but it hasn't, now its third day, and the pain doesn't stop at
all actually its not constant pain , sometimes smaller sometimes
more noticible that i can't fall asleep.

so i looked it up on wikipedia what does it say about class 1m:

"A Class 1M laser is safe for all conditions of use except when passed
through magnifying optics such as microscopes and telescopes. "

and i was looking through a telescope and an eye contact lens from
further reading i learned that such infrared laser can burn retina in
the eye ball, and cause the sight to be blurry. What do you
think , is my right eye permanently damaged? can retina
regenerate? is there any chance that my eye will heal after some
time? :-(

regards
Tom

 

wrote in @s13g2000prd.googlegroups.com:

Retina cannot regenerate. I'd suggest seeing an ophthalmologist, and fill
out any accident reports applicable at your place of employ.

 

Thanks for your responses. Yesterday I went to an emergency doctor ,
she poured some drops in my eyes and examined them with a flashlight.
She said that my right eye is injured and i should let it heal, and
not to look into laser in the future.
The doctor also prescribed some drops what i should pour into my eye.
I already tried them but i don't think it would help anything, because
the damage was done inside my eye. Anyway, today morning, i thought
the pain was gone, but this afternoon it came back even stronger, so
definitely something is hurt.

I don't intend to sue my employer, although actually my superior told
me that its safe to look through that telescope, but i just don't
want to mess with him, and i'm leaving that company anyway. Prior to
installation i also asked a producer whether its safe, and they sent
me some certificates
http://img402.imageshack.us/img402/3938/laserrm6.jpg saying that it
is totally safe, either class 1 and class 1m their laser products.

Only after i realized something is wrong with my eye i started
searching the net and found out that class 1m lasers are not safe when
look through the optical lenses, and i was wearing eye contacts and
looked through the telescope. That laser emits 16mW light, while
after focused it is hundreds of Wats inside the eye. I wrote them
back and tell what has happened, but they just stopped answering me.

I just feel bad that i trusted them, and i should have rather checked
it myself :-( anyway, as i said the pain is still strong, so
i'm just waiting till its gone, and hope my vision will recover.

 

previous link doesn't work, this should be ok:
http://images31.fotosik.pl/132/c2ba2de8561082cc.jpg

these are the certificates are received from a producer.

 

I'm not a doctor, but based on my experience with drops, *lots* of
experience, most of them penetrate the eye and work inside. There are
various tricks to this, otherwise the drops just drain into your sinuses
without much chance to work. If you weren't trained on these, call your
pharmacist or the doctor's office and ask.

 

look, you need to see a retina specialist. a general medical doctor
or emergency room doctor using a "flashlight" to examine your eye
sounds ridiculous.

anyway, if you had actual laser damage to your retina the effect would
be vision blurring or vision loss rather than pain. eye drops would
be almost worthless.

but of course I wholeheartedly agree that you should not look directly
at a laser again with a telescope!

 

It's not looking through lenses that's the problem. That warning was
probably left vague to err on the side of caution. Looking at a laser
through contact lenses doesn't change anything over a person who
doesn't need them to see clearly.

Looking through a telescope, however, is another question. It's kind
of counter-intuitive, what a telescope actually does. It makes stars
brighter, because they are so far away that they can't be resolved as
anything but point sources. So all the extra light gathered by a
telescope lens is focused on the same spot.

But for anything that's not an optical point source, the telescope
magnifies the size of the image. It's collecting more light, but
spreading that light over a larger area. The more the image is
magnified, the dimmer it is (the same amount of light spread is over a
larger area). As it turns out, any extended image (i.e. not a point
source) will be brighter to your naked eye than through a telescope.

A laser very far away might appear to be a point source to a
telescope, but lasers are also coherent light. Any lens larger than
the beam width is already collecting all of the light, so it wouldn't
look any brighter through the telescope than to the naked eye.

As an extended image, the beam will be enlarged by the telescope. The
total energy of the beam will be spread over a larger area of your
retina (whatever isn't absorbed or reflected by the lenses - glass and
plastic are fairly opaque to infrared).

That doesn't necessarily make it safe. I'm not familiar with the
nature of class 1M ratings. You can safely look at the sun with your
naked eye when it's reasonably close to the horizon, without risk of
vision loss. That's because the heat can be adequately dissipated by
your retina. But if you look through a telescope, the sun will be
dimmer (because it's magnified), but spread over a much larger part of
your retina. The heat will not be dissipated fast enough, and you'll
suffer permanent loss of vision.

Something similar could be true of the laser - it's safe to look at
with the naked eye, but not magnified (again, something your contacts
can't do).

 

What were the drops she gave you?? Can you provide the name (or, at
least, the active ingredient)??

I don't think anybody here is recommending that you sue anybody. They
ARE, however, talking about notifying your employer IMMEDIATELY about
the injury (very smart and very important) AND about pursuing a
Workers Compensation claim.

This is NOT the same as a lawsuit. It is designed to provide you with
medical, and certain other benefits, in the event of a work related
injury.

It sounds like this is ver good advice in your case.

I hope you're okay.

 

You should see a retinal specialist or at least a general ophthalmologist
ASAP.

 

it was an emergency hospital, but with different departments, and i
went to an eye specialist, on a separate floor, so it wasn't just a
general doctor. i could always go to another eye doctor to get a
second opinion tho.
And it wasn't a regular flashlight, definitely some special one, it
was emitting a vertical beam into my eye, and she was looking through
some sort of microscope, and examined both of my eyes, asking me to
look left, right, up and down. Before that she gave me some eye
drops to make my pupils bigger, i had to wait like half an hour.

i know, if my retina had been burned completely i would have lost my
sight, fortunately it hadn't, but something was damaged, the question
is what and how much?
normally i wear -2 contacts or glasses to see well, and after this
laser accident my right eye vision got worse, its like it requires -3
to see sharp, because that eye doctor allowed me to look through a
stronger lens and i could see sharper, but i don't know how many
diopters was that.
And also my right pupil is still noticeable bigger which is weird, and
of course that annoying pain doesn't go away. I'm still hoping i'll
recover from it, i'm pouring those eye drops every couple of hours
and started taking multivitamin pills, and drinking carrot juice,
which i read contains vitamin A , good for eyes.

the eye drops i got are called: diclofenacum natricum 0.1%, 5ml.
There are some ingredients listed on the box like: Polysorbate 80,
bor acid, sodium chloride, borax, water, and some other ingredient
which i can't translate, something with chloride.

Of course i told about this at my work, but it just made my boss mad
like he was afraid, so i told him that this only my business, as i
said i'm leaving that company anyway, for other reasons. I also had
to deal with microwaves transceivers what used to give me a headaches
for several days. For now i don't have anything to compensate, and i
hope i won't , i normally go to work as usual.

In the morning when i wake up , i almost don't feel any pain, but
later today it gets stronger, and afternoon its annoying, and its
strange because its like going down inside my head and to my right arm
and reaching my hand, like the pain is following some nerve path.

i don't think there are such specific doctors like 'retinal
specialist' in my country, only ophthalmologists, which is 'eye
doctor'. And i understand that its hard to examine an eyeball even
for a specialist. So thats why i don't know what exactly that laser
burned , whether only retina cells or some nerves too, what would
explain why i feel pain.

Mike, thanks for an interesting writeup.
a few words about that laser transceiver i was dealing with, here is
its front:
http://img255.imageshack.us/img255/3174/laserwk7.jpg
and the backplate with a telescope viewfinder i was looking through:
http://img142.imageshack.us/img142/6908/laser2jv8.jpg

that laser produces kind of a cone beam, so it was around 50cm
diameter infrared laser beam pointing at me, the source of the laser
was ~100 meters away.
And i think infrared can easily pass through glass, eg my infrared
keyfob to open the car. And those infrared lasers can be even
installed indoors behind windows, one of my colleague had such
installation. I read that only some special colored glass can block
infrared, so there are some amber protective goggles available. So
in my case my eye didn't pick a whole laser beam just a part of it
which was magnified by that telescope, but it was enough to hurt my
eye, i was installing it for about half an hour although , i wasn't
look through that telescope all the time, but i can't remember for how
long.

thanks all for your responses.
regards,
Tom

 

Seeing as he's posting from Poland, and the documents he referred to
are from Israel, that's a safe bet.

 

Collimated light from a laser is also effectively a point source, and it
can be focused to a diffraction-limited spot, just like starlight.
Now, we don't know how well collimated the source was in this case, but
if it was designed for long-range transmission with optics at each end
of the link, it's probably pretty good.

At close range, the collimating optics of a laser transmitter are likely
to be larger in diameter than the eye's pupil, so the pupil limits the
power that reaches the eye. A telescope could be large enough to
intercept much or all of the emitted beam. For example, if your pupil
is 3 mm in diameter, and you use a 10X telescope, the effective entrance
pupil of the scope will be 30 mm (or the objective lens diameter,
whichever is smaller).

At a distance, the beam will have spread to be larger than the telescope
objective, and the intensity will not change much over that diameter.
A 10X telescope could capture 100X as much light from the beam as the
naked eye.

That's why the warning about looking at lasers through binoculars or a
telescope. It really can drastically increase the captured energy. And
that energy can be focused to a point - a laser is *not* an area
source.

The saving factor in this particular case is that the laser was only 16
mW to start with, there are losses in the optics, and the beam has
probably spread substantially by the time it reached his position. Even
with a telescope, only a small fraction of the laser output entered his
eye.

Whether there is permanent damage is something a doctor should
determine, by actually looking at his retina.

Dave

 

good reply. the additional information is significant.

then you have seen an ophthalmologist and had a dilated fundus exam.
sounds like appropriate care. maybe additional testing with a nerve
fiber layer analyzer would have been more complete. maybe also a
thorough threshold-level visual field analysis too. perhaps they did
do these tests already.

the drops you are taking is called Voltaren in the US and many other
countries. it is used to reduce inflammation, and it is known that
deeper penetration of these drops, so as to provide retina-level
therapeutic effects, actually does work. so using the drops seems
appropriate too.

If it takes a stronger lens powers to see more clearly, then that does
not at all indicate that the health of your eye has been damaged. the
determinate is whether you can obtain clear 20/20 vision with intact
peripheral vision. doesn't matter if it takes you a -3.00 lens to do
it, or a -2.00 lens to do it. it would mean that you have gotten more
nearsighted, but if you can see clearly in that eye then that would be
normal.

 

Sorry.

I was in Yosemite, killing time while my wife napped ;-)

 

Thanks all for your feedback. yes, i am from Poland, and those
lasers come from Israel, we buy lots of electronics from there.
It seems like imageshack is having problems, so i'm reposting the
pictures of that transceiver:

front lenses, the smaller one emits the laser beam:
http://images34.fotosik.pl/134/2d0b2994a856bf7d.jpeg

the back panel, with a telescope i was looking through:
http://images31.fotosik.pl/134/7ad52d6abb360725.jpg

and here is a drawing describing it's laser beam divergence, the
longer the distance, the wider the beam:
http://images33.fotosik.pl/134/c32f912d089c7c90.jpeg

So that 16mW laser beam was definitely wider when entering the
telescope and then my eye. But as Dave said, telescope magnified
part of it, but i don't know to what degree, but according to what
i've read it could be increased to hundreds of wats focused to some
small laser spot scribing the retina. At the time i was looking
through that telescope i didn't feel any pain, but maybe i was just
distracted as i was standing on a crane platform about 5 floors above
the ground, and right after i finished i noticed that my right eye
vision got worse, and later that day the pain started.

Today i can tell that the pain got weaker, yesterday was the worst,
so i'm happy, i hope i will recover from it. Although my right pupil
is still bigger , i found out it may be 'Adie syndrome' but i'll be
worrying about it later, if it doesn't go away.

thanks for the info, i started reading about these Voltaren eye
drops, and found much more useful informations then i found in the
instruction provided with my drops, eg proper dosing.
http://www.drugs.com/cdi/voltaren-drops.html


once again thanks for your replies.
regards
Tom

 

i'm sure. its just some medicine to give to a concerned patient along
with a "medical-sounding" explanation so that they will leave
peacefully with a smile on their faces. Tobradex is effective for
that two.

 

No. The telescope cannot add power to the beam. It can concentrate
it or spread it out, but it cannot make the total energy more than 16
milliwatts (or whatever the laser actually put out).

 

"Mike Ruskai" wrote

Here important are the wats per unit area. The scribing take place when the
density (concentration) of energy is enough.
S*

 

wrote in :

Workman's comp is not suing your employer.