Although a laser will always pose a potential hazard to the retina, the use of scanners in practice and their speed of measurement are such that this risk is virtually non-existent.
Standards are used for the classification of lasers by numerous factors, including their power. The lasers (Class 2 or 3R) used in 3D scanners are of the low power type, and do not require the use of any specific protective equipment.
However, it is inadvisable to stare at the laser with eyes wide open for a period of several minutes... given the speed of movement of the beam, this would be difficult in any case!