Red laser is harmful to your eyes. With the unique features of laser light, it can be magnified by 100,000 times as it passes through your eyes. As the light passing to the back part of the eye, the retina, you may feel having a big floater that causes a lot of stress for you. Furthermore, you may suffer from blurred vision.
Red lasers nowadays are the common device adapted as pointer during presentations. Yet if this device is misused, it can cause risks to people's health. We already heard some reports about teachers, bus drivers and police, the red laser might cause temporary blindness, disorientation and headache. But as to what effects red lasers would bring to you, first of all we need to know what is laser. Laser produces radiation which looks like light but different from any other light from sun or lamps. The light from lamps spread evenly in all directions. Different wavelengths show different colors of lamp. However laser produces a very narrow wavelength light, strong directional, looking like a spot when pointing at some surface, even at the distance of over one hundred meters away. Laser pointers can emit light with wavelength between 630-670 nanometers, as red color light. Most of the light emitted by laser pointers is safe to human body. As to normal laser just blinking reflex could help protect our eyes. Pointing the red spot in eyes could cause temporary blindness. So far source of permanent damage is rare. Don't worry too much, but we 'd better not to do so.