Now that laser pointers have become increasingly prevalent on key chains, pens and promotional give-aways, we are often asked if laser pointers pose a threat to eyes. This is a difficult question, primarily for three reasons: (a) the power ratings for laser pointers vary widely by manufacturer and country of origin; (b) laser pointers have only been widely available for the past ten years; and (c) there are very few documented injuries from laser pointers that we can study.
Despite these limitations, it does appear that a laser pointer aimed directly into the eye from less than two feet away for more than ten seconds may damage the retina. Several case studies identified a permanent small scotoma (blind spot) after extended laser pointer exposure. The retina appears to be the only part of the eye at risk, since the other parts do not appear to absorb laser light.
There are a few factors that can reduce the likelihood of damage. The length of exposure is the most important; anyone exposed to direct laser light for at least ten seconds is doing so willingly, so accidental exposure is unlikely. Similarly, because the laser beam widens as it travels away from its source, its potency is significantly reduced after a few feet.
Most physician organizations recommend that laser pointers should not be used by children. However, if you allow your children to play with laser pointers, be sure to stress that laser pointers should never be directed towards the eye – animal or human – for any amount of time.