Re: Flash Blinded By Green Laser

From: Chris L Peterson (clp_at_alumni.caltech.edu)
Date: 01/01/05 

Date: Sat, 01 Jan 2005 22:10:16 GMT

On Fri, 31 Dec 2004 04:17:33 GMT, "Gary Honis" <ghonis@epix.net> wrote:

>I've been watching the news channel reports today on green lasers and the
>dangers to pilots. I've also been reading the messages here about using
>green lasers to easily point out objects in the night sky. I don't own a
>green laser pointer but I have a unique opinion of green lasers because I
>was flash blinded by one accidentally turned on by Howie Glatter at a star
>party. When a pilot says he was "flash blinded" by a green laser, I know
>what he experienced and the disorientation that results. I have also been
>a very active dark sky advocate for many years and I feel that astronomers
>should strongly discourage their use for the following reasons:
>
>They are a safety hazard and unsafe to dark adapted eyes.

If they are Class 3a lasers, under 5mW, they are absolutely NOT a safety hazard.
Naturally they have the potential to ruin dark adaptation.

>They are another form of light pollution.

A matter of personal opinion only. They have valid uses for astronomers, and
many would consider the benefits important enough to outweigh any minor issue of
excess light. "Pollution" is something we live with. I could argue that you
should never travel in any vehicle that burns fossil fuels because of pollution;
you'd probably argue that is an extreme position. I similarly consider not using
lasers as educational tools in astronomy because of "light pollution" an extreme
position (akin to not using goto scopes because of noise pollution).

>Their use is unnecessary.

Again, a matter of personal opinion. Many of us do find them useful enough as
teaching tools to qualify as "necessary".

>My initial report of the eye injury follows:

I don't mean to trivialize your experience, which was clearly disturbing. But
you don't appear to be describing an injury. Retinal injuries from lasers are
usually easy to detect by ophthalmic examination- was any damage documented?
More than one study has clearly demonstrated that casual exposure to visible
laser radiation from <5mW sources cannot cause damage. If you are continuing to
have problems, it suggests you may have one of several rare retinal diseases
that produce acute phototoxicity, where exposure to a bright light can cause
cell death. This is something you need to find out about, since long term
exposure to sunlight will cause problems, as will brief exposures to headlights,
flashlights, and other light sources that are capable of putting much more light
onto your retina than a 5mW laser.

_________________________________________________

Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

Relevant Pages

  • Re: Flash Blinded By Green Laser
    ... >we can stare, point blank, into 5 mW green lasers until we tire of the ... What I said was a _transient exposure_ would not cause damage. ... it is reasonable to limit the power of lasers brought to public ...
    (sci.astro.amateur)
  • Re: Rabbits and Lasers
    ... I've heard of people pointing lasers at airplanes and getting arrested. ... Any intently concentrated light in those wavelengths aimed directly into the eye is going to affect the eye more than any other wavelength, which is why the warnings came out with green lasers, not the red ones. ... I've experimented with how bright the reflections from 5 mWatt green lasers can get, and how much they can spread, off of various colored and textured walls and glass, and how it affects the eyes, and there is a danger factor of temporarily blinding someone if they're dark adapted to some degree. ...
    (sci.astro.amateur)
  • Re: Unauthorized Laser Illumination Event
    ... green lasers, though, are they? ... They are still not the most collimated beams around, ... nuisance to vision than a damage hazard. ... there are still more powerful lasers available. ...
    (rec.aviation.piloting)
  • Re: laser sight?
    ... about the wattage one green lasers .I did see that the 10mw + ones are ... control how lasers are labeled. ... most laws involving lasers are designed to manage usage. ... possibility of eye damage. ...
    (sci.astro.amateur)