'Smart' screens? Blue light can do invisible harm.

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By: Russell Pollitt

In social media workshops with parents and teachers a number of concerning issues normally surface: cyberbullying, porn, online privacy, sexting, inappropriate sharing, loneliness and issues around defamation. The recent case of a young Capetonian girl who was almost recruited by Islamic State online is also often a talking point. Seldom, however, are other health issues, like the effect of blue light from LED screens, mentioned. This can be just as damaging – in the long term. By RUSSELL POLLITT.

Earlier last week SABC chief operating officer Hlaudi Motsoeneng, called for the regulation of social media such as Twitter and Facebook. He was addressing government communicators at the University of the Witwatersrand School of Governance. “We must also regulate social media, it can’t be right (that) some people destroy other people’s lives,” Motsoeneng said. He said freedom of speech goes hand in hand with accountability and responsibility. There are, however, other reasons why we should be watching just how much we use social media.

Scientists in the US claim blue light emanating from screens is having a detrimental effect on our health. For a number of years scientists have been saying that being in the presence of blue light at night disrupts the body’s natural circadian rhythms because it suppresses the production of melatonin, a sleep hormone. However, melatonin is more than just a sleep hormone, it is also an antioxidant that could play a pivotal role in slowing the progression of cancer and other diseases.

The impact of blue light on melatonin production was only confirmed in 2001. Scientists found the blue light spectrum, 415-445 nanometer range, disrupts melatonin production.

Dr Richard Hansler, from John Carroll University in Ohio, has spent 20 years studying the effect of blue light on health. He claims he has learnt that the blue component in ordinary light is what suppresses the production of melatonin. Hansler says melatonin helps sleep but also plays a role in preventing diabetes, obesity, heart disease and a few types of cancer. Delayed melatonin production due to blue light exposure is causing many more problems than just insomnia. Optometrists, he says, are seeing higher levels of retinal stress in young people that could lead to the early onset of macular degeneration. In extreme cases this can cause blindness because it causes the loss of central vision – the ability to see what’s in front of you.

Blue light is widely used in all LED devices – phones, tablets, laptops and televisions. Blue light is part of the full light spectrum which means we are exposed to it via the sun everyday. However, night time exposure to this light – which is emitted at high levels by smartphones – has only been so heavily concentrated in our light sources for the past 10 or 20 years. (Previous incandescent bulbs don’t emit the same amount of blue light.) Smartphone screens emit high levels of blue light so that you can see them even at the sunniest time of the day.

Dr William Harrison, an optometrist in Laguna Beach, California, has been following the research on blue light closely. He claims it is compelling but says the medical profession is slow to catch onto the concerns that have been raised. “Here is what does not need research: 415 to 445 nanometers is super hot light, and if it’s really focused and brought up close – when you talking about a tablet six inches from a kids face – it’s got to be significant,” he says.

The more Hansler conducted his own research on the impact of blue light, the more he felt compelled to do something. In 2005 he and a group of physicists at John Carroll University developed lightbulbs that don’t emit blue light and goggles that block out that part of the spectrum. Hansler says there are screens that claim to filter out the blue light as well as applications that let you put your device in a bedtime mode where the light contains less blue and more amber. He is suspicious of whether these actually work and says more research needs to be done.

It is interesting to note that lens manufacturers are, for example, placing a coating on lenses. They claim the coating neutralises the blue light emitted from screens. This, they say, prevents eye fatigue, eye strain and even sleeplessness.

Blue light is not bad all the time. At times it is actually beneficial to health. Light tells us when to wake and when to sleep. Bright blue light sends a signal to the brain to stop producing melatonin; it also primes the brain to start producing the hormone again later – in theory when you are preparing to go to sleep. Some experts recommend that, in the morning, getting an hour of early sunlight without sunglasses is good. The light gets through the retina and signals to the pineal gland that controls melatonin production that it is day. At night, however, screen usage can convince our brains that it is morning and that they should, therefore, not produce melatonin. This can cause sleep disturbance and other potential problems.

The disruption of sleep has damaging side effects. It can leave you distracted and impair memory; it can also make learning harder. It can have an impact on thermoregulation, blood pressure and glucose homeostasis. Over a long period, insufficient sleep can lead to the build up of a neurotoxin that makes it even harder to get a good night's sleep.

Studies show that people whose melatonin levels are suppressed and whose body clocks are thrown off are more prone to depression. The higher incidence of depression globally could have, as a contributing factor, lack of sleep. Disrupted melatonin and sleep can also interfere with hormones that control hunger that, in turn, have the potential to increase obesity risk. Studies show that blue light is a 'carcinogenic pollution' and that, in mice, it correlates to higher cancer rates. A lack of melatonin is linked to higher rates of breast, ovarian and prostate cancers. Blocking blue light with amber glasses is linked to lower cancer rates.

Researchers are also investigating whether or not blue light leads to an increase in cataracts and if it could damage vision and harm the retina over time. Too much blue light, researchers think, could cause retina toxicity. It must be noted that most studies show the light needs to be held pretty close to the retina for this to happen. This may not replicate typical phone use – unless you are lying in bed with the phone close to your eyes.

While Motsoeneng’s idea of regulating Twitter or Facebook is probably going to be as successful as trying to regulate the taxi industry, religion or, for that matter, the amount of steps you take each day, it seems as if we would not be amiss to practise some self-regulation when it comes to the use of screens before bed. It also begs the question: Is the shift in education to more and more technology ultimately going to help future generations? DM

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