You should be careful when you are using a lase pointer. It can cause some eye damages if you look straight into the laser pointer. In spite of the fact that the power of the small laser pointer is only at the level of milliwatt, its luminance can be huger than the sunlight. Some advertisements of laser pointers said the light of laser pointer can light a match after focusing, therfore, if you look straight into the laser pointer, the light will focus right on the retina so that the retina will be burned and damaged. Just because of its high luminace, its scattered light is also very offending to the eyes. If you are using the laser pointer to watch the stars in the open, you should pay attention that the laser light should not luminate obstacles such as lense cone or tree leaves, or else, your eyes will be dazzling and it would take a long time to recover. This is because that in the darkness, the pupilla of the eyes will expand, which makes it more easier for the eyes to get affected and hurt.
