Most evenings, before watching TV or reading emails on his phone, Matt Nicoletti puts on a pair of orange-coloured glasses."My girlfriend thinks I look ridiculous in them," he said. But Nicoletti, 30, a hospitality consultant, says the glasses, which can block certain wavelengths of light emitted by electronic screens, make it easier to sleep.
Studies have shown that such light, especially from the blue part of the spectrum, inhibits the body's production of melatonin, a hormone that helps people fall asleep. Options are growing for block ing blue light, though experts caution that few have been tested for effectiveness and the best solution is to avoid brightly lit electronics at night.
A study of A study of 13 teenagers, published in The Journal of Adolescent Health, showed that when they donned orange-tinted glasses, known as blue blockers and shown to prevent melatonin suppression, in the evening for a week, they felt "significantly more sleepy" than when they wore clear glasses. The teenagers looked at their screens for a few hours on average before bed, and were monitored in the lab.
Older adults may be less affected by blue light, experts say, since the yellowing of the lens and other changes in the aging eye filter out increasing amounts of blue light. But blue light remains a problem for most people, and an earlier study of 20 adults aged 18 to 68 found that those who wore amber-tinted glasses for three hours before bed improved their sleep quality as against the control group that wore yellow-tinted lenses, which blocked only ultraviolet light.
Devices such as smartphones and tablets are often illuminated by light-emitting diodes, or LEDs, that tend to emit more blue light than incandescent products. Televisions with LED backlighting are another source of blue light, though because they are typically viewed from much farther away than small screens like phones, they may have less of an effect, said Debra Skene, a professor of neuroendocrinology at the University of Surrey. "Anything that decreases blue light exposure at night will be helpful," said Christopher Colwell, neuroscientist at the University of California."Some gamers swear by those orange-tinted goggles." But orange glasses are not a panacea, Skene said. "It isn't just get rid of the blue and everything's fine," she said.
The intensity of light, in addition to colour, can affect sleep, and not all brands of orange-tinted glasses have undergone independent testing for their ability to aid sleep. Nicoletti says he also uses applications designed to alter the blue light impact of his devices depending on the time of day: an app called f.lux for his computer and Twilight for his mobile phone. Other ideas are proliferating. An Ohio company , for example, offers filters to block blue light by covering the screens of electronic devices like the iPhone or iPad. Other company products include "low blue" LED lights and orange eyewear.
During the daytime, experts say , exposure to blue light is good. Sunlight, which contains different wavelengths of light, is the best. "That's what our brain knows," said Kenneth P Wright Jr., director of the sleep & chronobiology lab at the University of Colorado. A 2013 study he led, showed just how different things can be without nighttime lights: After participants had camped in the mountains for a week, their bodies began to prepare for sleep about two hours earlier than normal.
Short of cutting out all evening electronics, experts say , it's advisable to use a small screen; dim the screen and keep it as far away from the eyes as possible; and reduce the amount of time spent reading the device. "If you can look at the iPhone for 10 minutes rather than three hours, that makes a lot of difference," Dr Skene said.
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