How strong does a laser have to be to damage your eyes?

Eye damage from a pocket laser is unlikely, but could be possible under certain conditions. Red laser pointers that are "properly labeled" in the 3-5 mW range have not caused eye damage -- no retinal damage has been reported -- but there are very real concerns. One is pointers not manufactured to federal specifications. read more

” Considering visible laser (e.g. red He-Ne laser), below about 50 mW you can close your eyes quickly enough that the energy absorbed is insufficient to cause permanent eye damage. read more

A laser is a pure tone, only one wavelength. The coherent light will be more damaging. The common red laser pointer is a diode laser, really just a special type of transistor, or diode. Because of the unique features of laser light, it is magnified by 100,000 times as it passes through the eye. read more

But at 1 mW, the laser can and will damage your eyes if you stare into it. However, most visible lasers are considered relatively safe under 5 mW. That is because for lasers at this power, though they have more power than needed to injure your eye, the damage occurs slower than you blink. read more