Most evenings, before watching late-night comedy or reading emails on his phone, Matt Nicoletti puts on a pair of orange-colored glasses that he bought for $8 on the Internet. "My girlfriend thinks I look ridiculous in them," he said. But Mr.Nicoletti, a 30-year-old consultant in Denver, insists that 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  , _ the body's production of melatonin ,which helps people fall asleep. Options are growing for blocking blue light, though experts caution that few have been adequately tested for effectiveness and the best solution remains avoiding brightly lit electronics at night. A Swiss study of 13 teenage boys, published in August inThe Journal of Adolescent Healthshowed that when the boys wore orange-colored glasses, also known as 'blue blockers' and shown to prevent melatonin, in the evening for a week, they felt "significantly more sleepy" than when they wore clear glasses.The boys looked at their screens, as teenagers tend to do, for at least a few hours on average before going to bed, and were monitored in the lab. Older adults may be less affected by blue light, experts say, 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 orange-colored glasses for three hours before bed improved their sleep quality considerably relative to a control group that wore yellow-colored lenses, which blocked only ultraviolet  light. LEDs used in devices such as smart phones, tablets and televisions tend to emit more blue light than incandescent products . LEDs are also increasingly popular as room lights, but "warm white" bulbs, with less blue, tend to be a better choice than "cool white" for nighttime use. The lighting company Philips also makes a reduced-blue LED bulb, meant to be used before bedtime."In theory, anything that will decrease that blue light exposure at night will be helpful." said Christopher Colwell, a scientist at the UCLA, "I know some gainers who swear by those orange-colored glasses." But orange glasses are not a panacea . Dr. Skene said."It isn't just getting rid of the blue and everything's fine," she said. The intensity of light, in addition to color, can affect sleep, she said, and not all brands of orange-colored glasses have undergone enough independent testing for their ability to aid sleep. During the daytime, experts say, exposure to blue light is good. Best of all is sunlight, which contains many different wavelengths of light."That's what our brain knows," said Kenneth P.Wright Jr., director of the sleep and chronobiology  lab at the University of Colorado, Boulder. A 2013 study he led, published in the journalCurrent Biology, 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 rather than a large one; 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. The purpose of this article is to   _  .
advertise a brand of orange-colored glasses which can block blue light question the effectiveness of orange-colored glasses on the market introduce a kind of orange glasses that may help people sleep better teach readers about the most effective ways to have a better sleep
Question: Most evenings, before watching late-night comedy or reading emails on his phone, Matt Nicoletti puts on a pair of orange-colored glasses that he bought for $8 on the Internet. "My girlfriend thinks I look ridiculous in them," he said. But Mr.Nicoletti, a 30-year-old consultant in Denver, insists that 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  , _ the body's production of melatonin ,which helps people fall asleep. Options are growing for blocking blue light, though experts caution that few have been adequately tested for effectiveness and the best solution remains avoiding brightly lit electronics at night. A Swiss study of 13 teenage boys, published in August inThe Journal of Adolescent Healthshowed that when the boys wore orange-colored glasses, also known as 'blue blockers' and shown to prevent melatonin, in the evening for a week, they felt "significantly more sleepy" than when they wore clear glasses.The boys looked at their screens, as teenagers tend to do, for at least a few hours on average before going to bed, and were monitored in the lab. Older adults may be less affected by blue light, experts say, 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 orange-colored glasses for three hours before bed improved their sleep quality considerably relative to a control group that wore yellow-colored lenses, which blocked only ultraviolet  light. LEDs used in devices such as smart phones, tablets and televisions tend to emit more blue light than incandescent products . LEDs are also increasingly popular as room lights, but "warm white" bulbs, with less blue, tend to be a better choice than "cool white" for nighttime use. The lighting company Philips also makes a reduced-blue LED bulb, meant to be used before bedtime."In theory, anything that will decrease that blue light exposure at night will be helpful." said Christopher Colwell, a scientist at the UCLA, "I know some gainers who swear by those orange-colored glasses." But orange glasses are not a panacea . Dr. Skene said."It isn't just getting rid of the blue and everything's fine," she said. The intensity of light, in addition to color, can affect sleep, she said, and not all brands of orange-colored glasses have undergone enough independent testing for their ability to aid sleep. During the daytime, experts say, exposure to blue light is good. Best of all is sunlight, which contains many different wavelengths of light."That's what our brain knows," said Kenneth P.Wright Jr., director of the sleep and chronobiology  lab at the University of Colorado, Boulder. A 2013 study he led, published in the journalCurrent Biology, 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 rather than a large one; 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. The purpose of this article is to   _  .
A. advertise a brand of orange-colored glasses which can block blue light
B. question the effectiveness of orange-colored glasses on the market
C. introduce a kind of orange glasses that may help people sleep better
D. teach readers about the most effective ways to have a better sleep
Answer: