Possible eye damage from 1mW laser line?

Hello i am quite scared right now so i apologize for the long story...


Yesterday at the office, an external firm fixed a decoration on the wall halfway the hallway. To fit this, he used a laser tool that was projecting a vertical line to the front on the wall but also to the left and right into nowhere meaning the beginning and ending of the hallway. He used a Hilti pm 4-m multiline laser tool that stood on the ground at foot height. The specs are <1mW 635nm Class 2 with a battery life of 8 hours.

Ok now before i continue you must know this: The hallway left side is a white wall and the right side are diffused windows and the sun was shining very bright for this time of the year. It was around noon when the sun was at it's highest.

So next i had to pass through the hallway and with the sun being that bright, i focused my eyes on the ground not knowing that the laser thing was standing there. Next i felt something that i can best describe as contraction of my eye muscle of some sort, like when you get from a dark room too a bright lit room your eyes do something "strange" ...or when you get hit by a laser, it's some kind of "blast" in your eye that you not hear nor feel but it is there. This happened for about 2-3 seconds.

At this point i just thought it was just the sun shining in my eyes so i moved on, and suddenly at the middle of the hallway, i saw the laser machine at my feet that was shining a line towards me on the ground, not in my eyes because i was to close at this point.

So i began to wonder. because in the past i had a supermarket laser shone in my eyes and it felt like the same "blast". Back then the blink reflex saved me but now i did nothing special because at no point when i was walking toward the laser, again not knowing it was there, i never saw a light that was bright enough to draw my attention like every laser should when in use?


So my first question is, can the sunlight de-brighten the start point (not the projection) of a laser so that it's not noticable but still in use? If so, will it still have the dangerous effects/strength?
Second, can a laser still damage your retina if shone in your peripheral vision?
Third, should i be concerned that this laser damaged my eyes given the "blast" time, if it was from the laser line?

Any thoughts on this? Because i really don't have a clue and don't know if i should be worried.. I added a drawing to illustrate this story.


At final i do mainly computer work, already slept pretty badly before this incident so pretty tired.

Because the only thing i am feeling is a sort "hit on the eye" pain and inflammation at the surface. I can't say i am seeing more blurry than usual and i can't say i see more floaters than usual. Also i don't see any afterimages i think.

Hopefully someone can help me! Thanks!

real art

If the problem is still there at the end of the day, SEE A DOCTOR. It sounds like you may have high sensitivity to light or perhaps something else that may cause it. If you have problems sleeping, mention that to the doctor too. Things like sleep apnea can make you tired all the time and trigger a whole host of other things.

If it was an actual 1mw laser, you could stare into it for minutes and not have an issue (not encouraging doing that on purpose though). I have no idea whether the lasers used in those types of devices are actually that low powered though.

Yea 1mW won't do anything to your eye unless you stare right into it for a long while. I wouldn't worry about it. See a doctor if your symptoms don't disappear after a few days

Welcome to LPF.
The HomeDepot PDF manual for this model - Hilti PM 4-m multi line laser tool states that it is a 0.95mW 620-690nm Class 2 laser : HERE
The advice given is not to stare into the beam. But if you did not do that, you should be fine. Fyi sunlight does attenuate a beam.
See an opthamologist if it does not improve after a week.
Ophthalmology is a branch of medicine dealing with anatomy, physiology and diseases of the eye. They specialise in medical and surgical eye problems.
Be more careful when working around lasers in future.

I know this is an old post, but for information for others and after spending some time reading on the subject, since I had an unfortunate incident with a much higher powered laser not too long ago (with googles though), I can with fair centainty say that you are safe.

Here's a quote from wikipedia:
"Van Norren et al. (1998)[27] could not find a single example in the medical literature of a <1 mW class III laser causing eyesight damage. Mainster et al. (2003)[28] provide one case, an 11 year old child who temporarily damaged her eyesight by holding an approximately 5 mW red laser pointer close to the eye and staring into the beam for 10 seconds, she experienced scotoma (a blind spot) but fully recovered after 3 months. Luttrull & Hallisey (1999) describe a similar case, a 34 year old male who stared into the beam of a class IIIa 5 mW red laser for 30 to 60 seconds, causing temporary central scotoma and visual field loss. His eyesight fully recovered within 2 days, at the time of his eye exam. An intravenous fundus fluorescein angiogram, a technique used by ophthalmologists to visualise the retina of the eye in fine detail, identified subtle discoloration of the fovea."

Here's a link to the source: http://en.wikipedia.org/wiki/Laser_safety#Laser_pointers http://en.wikipedia.org/wiki/Laser_safety#Laser_pointers

Sajo said:

I know this is an old post, but for information for others and after spending some time reading on the subject, since I had an unfortunate incident with a much higher powered laser not too long ago (with googles though), I can with fair centainty say that you are safe.

Here's a quote from wikipedia:
"Van Norren et al. (1998)[27] could not find a single example in the medical literature of a <1 mW class III laser causing eyesight damage. Mainster et al. (2003)[28] provide one case, an 11 year old child who temporarily damaged her eyesight by holding an approximately 5 mW red laser pointer close to the eye and staring into the beam for 10 seconds, she experienced scotoma (a blind spot) but fully recovered after 3 months. Luttrull & Hallisey (1999) describe a similar case, a 34 year old male who stared into the beam of a class IIIa 5 mW red laser for 30 to 60 seconds, causing temporary central scotoma and visual field loss. His eyesight fully recovered within 2 days, at the time of his eye exam. An intravenous fundus fluorescein angiogram, a technique used by ophthalmologists to visualise the retina of the eye in fine detail, identified subtle discoloration of the fovea."

Here's a link to the source: http://en.wikipedia.org/wiki/Laser_safety#Laser_pointers

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Hasen't it already been established he/she was safe? :shhh:

But it's well known 1mW won't cause any damage(unless you look at it for a loooooong period of time).

Best of all, avoiding looking into the laser regardless of any output power is still the safest way to avoid blind spots

+1 for the effort into researching.

Tha Greenlander said:

Hasen't it already been established he/she was safe? :shhh:

But it's well known 1mW won't cause any damage(unless you look at it for a loooooong period of time).

Best of all, avoiding looking into the laser regardless of any output power is still the safest way to avoid blind spots

+1 for the effort into researching.

Click to expand...

I guess it was established already - I was just reassurering him(and anyone else who might be interrested in this type of scenario.) with actual cases/"hard evidence" - he did seem quite worried.

Anyways - thanks for the +1