"Our results show that the so-called 'frequency doubled' laser pointers, usually green, blue and violet pointers, can be particularly dangerous even if they seem safe to the user," he said.
"For example, some laser pointers can output widely different laser power depending on the temperature. They can appear perfectly safe at room temperature only to become much more dangerous outside and vice-versa. Moreover, as pointers are being used they heat up, so a pointer that initially seems safe can subsequently become highly powerful and dangerous.
"Other lasers can produce safe levels of coloured light, but at the same time emit high power invisible infrared light. A person looking at the visible green light would estimate the laser to be safe and the much greater power and danger would go unnoticed until injury occurs."
Laser pointers have been controversial, in particular because they have been shined into the eyes of plane and helicopter pilots and train drivers, with an average of 1,500 reported attacks per year in the UK. They can cause permanent or temporary eye damage, and it is a criminal offence to do so.
If they're so dangerous, why are they putting them in the headlights for all the new cars?
(Score: 3, Touché) by ledow on Wednesday October 11 2017, @02:55PM (6 children)
If you're relying on your night vision to drive, you're doing something wrong.
That's precisely why we invented headlights.
(Score: 0) by Anonymous Coward on Wednesday October 11 2017, @03:05PM
(Score: 5, Informative) by Thexalon on Wednesday October 11 2017, @03:13PM (4 children)
Of course you are relying on night vision. Your headlights show you some of what's in front of you. They don't tell you what's next to you or what's behind you. Your pupils dilate quite a bit, even with your lights on. And then some jerk comes the other direction in an illegally jacked-up pickup truck with super duper bright halogen lights and your pupils now have to close up again. And it takes them a while to dilate again.
A recommended move when somebody like that is coming towards you is to look at the line on the side of the road (or the side of the road itself if there is no line there) when they get close so that your pupils don't close up as much while still telling you which way to stay on the road.
The only thing that stops a bad guy with a compiler is a good guy with a compiler.
(Score: 2, Informative) by Anonymous Coward on Wednesday October 11 2017, @04:30PM (1 child)
"Night vision" is a poorly-defined term, so I'm not saying you're wrong to use it that way, but it seems to be causing confusion in this thread.
Usually, people people use "night vision" to mean scotopic vision, which is very slow (minutes) to recover, and leaves you essentially blind. If you were driving by scotopic vision, and got headlights flashed in your eyes, you would be pretty likely to crash or run off the road. Fortunately, if you're driving with any headlights (even crappy optics with decade-old long-life bulbs in them), you're not using scotopic vision.
Ordinary pupil dilation/contraction that you refer to is a much faster process (seconds), and while recovering, you'll still have some visibility in the brightest and/or closest part of your headlight beams; you will be overdriving your headlights (as seen through your contracted pupils), so there's certainly some potential for a crash in those seconds, but you're unlikely to run off the road.
(Score: 2) by Phoenix666 on Wednesday October 11 2017, @05:45PM
There are the after images to contend with, too. Even with your mirror flipped the halogens are blinding and cause your vision to dance with those after images. When they're coming the other way on the other side of the highway, with no blinds to prevent it like they have on the autobahn, it's even worse. Looking at the sideline the way they taught you when seeing high beams on old style headlights isn't enough; you have to try to screen them out with your hand.
Washington DC delenda est.
(Score: 2) by number11 on Wednesday October 11 2017, @07:15PM (1 child)
Aw... I'm not supposed to use the RPG?
(Score: 2) by hendrikboom on Thursday October 12 2017, @12:53AM
The role-playing game? I suppose you could do that while you're parked by the side of the road waiting for your eyes to recover.