Anybody who is holding a laser should never stare at the laser beam or spot, and never try to abuse it unless authorized operation.
Laser radiation predominantly causes injury via thermal effects. There are just relatively small amounts of laser light can lead to permanent eye injuries. For instance, moderate and high power lasers are potentially hazardous because they can burn the retina of the eye, or even the skin. Low powered lasers less than 50mW has no hazard to human eyes or skins even though a direct watching or staring.
Sufficiently powerful lasers in the visible light will penetrate the eyeball and may cause heating of the retina. Infrared laser are especially dangerous since human eyes has no reaction and response to invisible beam. People may not feel pain or notice immediate damage to their eyesight even they are exposed to high power infrared lasers. Terrible retina damage might be occurred without indication.