What is the maximum distance can a laser permanently blind someone?

[cheejiayuan512]

Agreed. As a newbie, I have spent 2 to 3 times more $$$ on quality accessories than on the laser itself. Safety is really important!

 

[Antharak]

^^ :crackup:

 

[Benm]

Safety has less to do with the lasers parameters than the wise operation from it's owner. Laser safety unfortunately comes down to experience and education. Stay safe!

It should really come from education, not experience.

Given you have two eyes you can make a major mistake once and still have vision left (albeit 2D), calculating risks is preferred here.

What exposure level is actually considered dangerous remains a bit debatable though. Something like 1 mW/cm2 (evenly distributed) seems like a fairly safe limit. Bear in mind that 1 mW/cm2 is about the amount of light you receive when looking directly into the sun under nearly worst-case conditions (worst case is about 1.4 mW/cm2, at noon in the desert on a very clear day). Then again, looking directly into the sun is advised against and can actually do some damage to your eyes, though mostly not permanent. People tend to do this around solar eclipses and protective eyewear is strongly advised if you ever directly observe one (which i do recommend doing since its simply amazing, just don't stare with the naked eye).

 

[millirad]

^ True, the experience should not be gotten without education first. With higher powers easily accessible to novice laserists than when you and I started, there are no second chances.

 

[steve001]

Free version Laser Visuals - Scanguard laser show analysis software

The Scanguard laser show safety analysis software is designed to help situations commonly encountered by laser operators, and make the whole assessment process much more manageable, in providing detailed information on exposure levels and MPEs for a wide range of laser effects. Scanguard is the first software in the world to offer the analysis of complex laser effects, removing much of the guesswork and headache out of checking the safety levels of such effects.

 

[Benm]

Such software is useful to calculate MPE limits for a laser show that projects onto an audience. In such cases a failsafe is required that instantly powers down the laser in case of a mechanical failure to the scanning system as well.

For lasers that are not moving around the calculations are far easier, all you basically need are power, initial beam diameter, divergence and distance. Downside is that the first 3 are often specified as typical or even worst-case figures, so a real laser (pointer) may be more hazardous that initially thought.

 

[hakzaw1]

At all LEMs high power laser projectors are everywhere--we all are required to sign an insurance waiver- and thus have full access- including all the danger zones- and you wont see many wearing protection- most have been around lasers so long a sixth sense has become second nature- to keep any direct eye shot from happening.--- BUT if setting up - aligning or any other similair things the glasses are on .

read my thread on camera safety--