Laser Pointers have turned out to be commonplace as they are an effective tool in presentations and they are cost-effective/ inexpensive. However, finding out how safe that laser pointer is in your desk drawer or your child’s hand isn’t easy. Most people are concerned that laser pointers are harmful to the naked eye. So this is the bigger question to ask – Are laser pointers harmful enough to hurt your eyes? Is prolonged exposure of a laser pointer to the naked eye a cause of concern?
It is considered. Especially with more and more people drifting towards the choice of laser light for their vehicle’s headlight. It’s a growing cause of eye ailments and can hamper the vision of pilots, drivers, or bystanders.
Contents
Flash blindness is the most common problem/ condition associated with laser pointers. It occurs when the eye is dazzled after being exposed to bright light. Many people experience flash blindness after having their picture taken by a camera with a flash. The condition is usually temporary and people tend to regain their vision after a minute or a few seconds.
Flash blindness can prove dangerous in case it occurs while someone is performing a task that is visually demanding like driving a car. There have been various cases of airline pilots, flash blinded when someone on the ground aimed a laser pointer at the cockpit. In 2010 only, the Federal Aviation Administration brought to notice that they had recorded 2,836 such instances.
More permanent repercussions may result in retinal damage. The retina is a tissue that lines the back of the eye. In addition, the retina is responsible for capturing an image that we see and sends it to our brain. This leads to the perception of our vision. In case the retina is damaged, then vision loss can be permanent. Therefore, a laser can lead to irreversible vision loss in case it damages the retina.
The light of the laser is concentrated into a narrow beam. If aimed at an individual’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 that is focused to a point is brighter than the equivalent area of the sun’s surface. This can lead to a detectable change (injury) to the retina, in case the laser remains in one spot for a few seconds. This is why in some countries such as the U.K., laser pointers are limited to 1 Milliwatt or less.
The safety of visible lasers generally relies on a blink reflex and/or aversion response where bright light leads to blinking and/or moving out of the light. As the blink reflex has been known to limit the exposure time, lasers that have an output of less than about 5 Milliwatts are usually considered safe for the public to use.
In the U.S., regulation of laser pointers is in the hands of the Food and Drug Administration. These lasers come with a warning label for alerting the consumer about the danger. Most of the lasers that are used in toys and games are labelled “Type I”. Type I lasers possess a power output of under 0 .4 Milliwatts. Such lasers are incapable of causing any damage to the retina. Usually, laser pointers are classified as Type II or IIIA. The power output of these laser pointers ranges between 1 to 5 Milliwatts. Theoretically, this much power is considered sufficient enough to damage the retina.
Journal ‘Ophthalmology’ published a paper in 1997 that demonstrated damage of retina due to continuous exposure to light from a laser pointer can occur in just 10 seconds. Practically, it would be difficult to cause damage to the eye because the eye makes continuous small movements making it impossible to attain 10 seconds of continuous exposure. There have been no such cases of reported permanent damage resulting from laser pointers that are labelled type II or IIIA.
A paper was published recently in the New England Journal of Medicine that demonstrated a permanent vision loss in a 15-year old Switzerland who purchased a laser off the internet. The laser was unregulated and carried a power output of 150 milliwatts, that consists 30 times more powerful than laser pointers that are marketed in the US. the boy in general was using the laser pointer to burn holes in paper and to pop balloons. The boy shined the laser pointer in his own eyes and thereafter suffered permanent, moderate vision loss.
While it is unlikely many lasers that are used in the games, toys, and laser pointers can lead to permanent damage in your eyes, it is theoretically possible therefore caution should be maintained. Shining a laser pointer in someone’s eye while that person is performing a particular visual task can result in flash blindness and may even result in an accident. Children should avoid playing with lasers that are unsupervised. They should also avoid using lasers that are not properly labelled. Some basic rules with lasers –
Certain government authorities have even banned or restricted laser pointers. Some of the states and cities have or have proposed an age limit on buying or using laser pointers. The United Kingdom has banned the use of class 3A laser pointers. Laser pointers can be categorized as high-tech tools and not toys.
Therefore, the improper use of laser pointers can result in persistent retinal damage and visual impairment. Before carefully purchasing the laser pointers via the internet, the public needs to be more aware of the danger posed by these, specifically to children and adolescents.
The best way to treat your eyes is to visit your eye care professional and get your eyes checked regularly. He will be able to assess the best method of treatment for your eye ailment.
The FDA says that in case you have a laser pointer that is not labelled or in case you do not trust the labelling, consider the following:
The FDA also explained why blue- and violet-light lasers can be especially dangerous. The human eye is less sensitive to blue and violet. So, while a victim would react quickly to a red or green laser, that individual may not blink or turn away as fast from an equally powerful blue or violet light, creating a greater likelihood of injury.
Other macular injuries documented in the study included hemorrhages in a different retinal layer, a macular pucker (when cells proliferate on the surface of the retina, causing visual impairment), a retinal disruption, and a cavity in the retina. Only 4 eyes (29 percent) improved spontaneously with an increase in vision, whereas 10 eyes (71 percent) need intervention, including Vitrectomy (surgery in which the vitreous gel in the eye is removed and an operating microscope and small surgical instruments are used to remove blood and scar tissue that accompany abnormal vessels in the eye).
