LED lights have been growing in popularity over incandescent and compact fluorescent lights because they last longer and use less energy. They also are less dangerous if broken than their counterpart, as fluorescent lights contain a small amount of mercury inside the tubing that can be released as vapor if broken. The numerous benefits of LED lights have caused their commercial popularity to skyrocket and they are now replacing standard streetlights in many cities around America including Seattle and New York. According to statements recently released by the American Medical Association, this change may be bad for our eyes and our sleep hygiene.
White LED lights have a color temperature of 4000-5000 Kelvin. This color temperature is a measure of the amounts of different colors emitted from a light source and a higher rating means more blue light. This concentrated blue light is the problem. It is recommended that outdoor lighting at night have less than 3000 K. At night this type of light causes glare that causes our pupils to react by constricting. The blue light makes it difficult to see clearly at night, which poses an obvious threat to nighttime drivers and pedestrians. Studies have also shown blue light to be damaging to the retina at sufficient levels.
LED lights are also five times more effective at suppressing melatonin at night than the formerly used bulbs for street lighting. Why does this matter? Melatonin is a hormone produced in our brains that increases in the evening anticipating the onset of darkness and prepares us for sleep. Decreased sleep quality can result in daytime sleepiness and impaired functions and has even been linked to obesity. Melatonin also happens to be an antioxidant and we never want to suppress our body’s own natural antioxidants!
What can we do to protect ourselves and maximize our health? We may not be able to stop to switch to LED on our streets, but the hope is that recent studies on the health hazard will prompt the use of shields on street lights to minimize glare and the risk for drivers. For the LED lights in our workplaces and homes, we should use LED lights with the lowest level of emitted blue light and dim lights at night whenever possible to minimized the effect on our eyes and our sleep cycle.