There are indeed different levels of power and thus intensity.
I had green laser pointed at me last week while I was on 8nm final and this was quite powerful.
Have a look at this link
Green Laser,Laser Beam Optics,Laser Safety Glasses : Dragon Lasers
and this movie from youtube
YouTube - Hulk Ultra 400mW high power green laser
I'm sure these could some serious damage.
Be careful.
Lorel