In article ,
Larry Dighera wrote:


What magnitude of laser power would you estimate to be required to
cause retinal damage at say 1 mile for what period of time?

The problem is not damage, it's "dazzle" -- having what seems to be a
_very_ bright light more or less in the center of your field of view and
coming straight into your eyes.

Yes, you blink, or look away -- but after you open your eyes the bright
incoming light may still be there, very close in angle or position to
the terrain or the instruments you have to look at, so you can't really
easily block it. Even with the laser positioned somewhat off to the
side there may be a lot of bright scatter from dirt or scratches on the
windshield, very similar to the situation of driving a car with a dirty
or scratched windshield (or just with aging eyeballs) looking into the
bright headlights of oncoming cars. And, any night vision adaptation
you may have had is gone (night vision can be wiped out considerably
faster than it can be restored).

All of these effects can be produced at light intensities way, way below
the level that produces any permanent damage to the retina. Though I'm
no expert on this subject, I have also been told that sustained exposure
to this kind of illumination in a situation where you can't just "turn
it off" and where the light levels, although below permanent damage, are
well above what leads to you to blink, and especially if they occur in
stressful situations with demanding performance requirements, can
rapidly lead to various kinds of psychological distress.