A laser pointer or laser pen is a small handheld device with a power source (usually a battery) and a laser diode emitting a very narrow coherent low-powered laser beam of visible light, intended to be used to highlight something of interest by illuminating it with a small bright spot of colored light. Power is restricted in most jurisdictions not to exceed 5 mW.
A laser’s light is concentrated into a narrow beam. If aimed at a person’s eye from close up, most or all of the light goes through the pupil. The already-concentrated light is further focused by the lens onto a sharp (“diffraction-limited”) dot on the retina.
The power density from a 1 milliwatt laser, focused to a point, is brighter than the equivalent area of the sun’s surface. This can cause a detectable change (injury) to the retina, if the laser stays in one spot for a few seconds.
The light bulb gives light in all directions so you only see a small part of the whole. As you move away from the bulb, you see a quarter of the light every time the distance is doubled. A laser gives light in one small beam. If it gets into the eye, you receive all the laser’s energy, not just a fraction.
The FDA does offer advice to help consumers identify which laser products might be dangerous and how to use devices safely. The agency is making laser safety awareness a priority just as a new study has shown that even the briefest exposure to high-powered blue handheld laser products can cause serious eye injuries.
Researchers have concluded that the wide availability of these devices, which are often marketed as toys, could lead to an epidemic of eye injuries, according to a study recently released by Ophthalmology, the journal of the American Academy of Ophthalmology.
Permanent damage to the eye can result from retinal damage. The retina is a tissue that lines the back of the eye and is responsible for capturing the image we see and sending it to the brain resulting in the perception of vision. If the retina is damaged, then permanent vision loss can result. So a laser can cause permanent vision loss if it damages the retina.