When we’re not in front of a TV or computer screen, many of us spend the day attached to our phones, checking them long after the natural light has faded outside.
It’s increasingly recognised that the blue light emitted from these devices can disrupt our body clocks and sleep patterns, but now doctors warn it may also damage our skin and eyesight.
Much of the research is at an early stage — but meanwhile, chief medical officer Dame Sally Davies has said that at the very least people should turn off their tablets, phones and computers before bed.
‘There is increasing concern about the impact of computer or smartphone screen use and “blue light” upon human health,’ she said in her annual report in March last year. ‘Research is ongoing and this is an important area of investigation.’
Here’s what emerging evidence suggests:
IT MIGHT HURT MY EYES
Blue light, also known as high energy visible light (HEV), is part of the visible light spectrum, which is formed of red, orange, yellow, green, blue, indigo and violet light.
Blue to violet light has the shortest wavelength on the spectrum — the shorter the wavelength, the higher its energy.
Last year, U.S. scientists published research suggesting that blue light might damage vision and speed up the onset of blindness. Researchers at the University of Toledo found that prolonged exposure to blue light triggers toxic molecules in the eye’s light-sensitive cells, killing them off — a process that leads to macular degeneration, a common cause of sight loss.
The lab-based study, published in the Journal Scientific Reports, found that blue light triggers retinal — a protein in our eyes that senses light — to create poisonous molecules in the photoreceptor cells (specialised cells which respond to light).
There were no changes when the cells were exposed to green, yellow or red light — only blue light affected them.
Commenting on the findings, Dr Ajith Karunarathne, an assistant professor in the university’s department of chemistry and biochemistry, said: ‘We are being exposed to blue light continuously and the eye’s cornea and lens cannot block or reflect it. It’s no secret that blue light harms our vision by damaging the eye’s retina. Our experiments explain how this happens and we hope this leads to therapies that slow macular degeneration.’
Romesh Angunawela, a consultant eye surgeon at Moorfields Eye Hospital and co-founder of Ophthalmic Consultants of London, agrees: ‘Blue wavelength light from digital devices carries more energy to the retina and in particular, the macula [responsible for central vision].
‘Some ophthalmic scientists have suggested that this could increase the risk of developing age-related macular degeneration. Long term studies are required to critically assess this proposed risk.’
It may be especially harmful to look at phones, glowing with blue light, in the dark, explains Dr Karunarathne: ‘[When it is dark] your pupils are so dilated that everything coming from the device gets in.’
Yet while there is no conclusive evidence that blue light from our phones could cause vision loss, it is widely recognised that spending hours in front of devices can lead to digital eye strain.
This is characterised by headaches, fatigue, blurred vision and dry eyes. ‘Blue wavelength light scatters more than other wavelengths and can result in digital eye strain from extended use of devices,’ adds Mr Angunawela.
Screen use is also linked to a raised risk of dry eyes. This is because we don’t blink as much when staring at them — we normally blink 15 times a minute, but a 2013 study published in the journal Optometry and Vision Science, suggested we blink half to a third that often when on our devices. Optometrists recommend the 20-20-20 rule — look away from the screen every 20 minutes and then focus on an object 20 ft away for 20 seconds.
It’s thought that blue light, like UV light, can prematurely age and damage the skin — indeed some dermatologists believe that they can spot someone who takes a lot of selfies, or identify which ear they hold their phone to, just by examining their skin.
U.S. dermatologist Dr Zein Obagi has said: ‘You start to see a dull, dirty looking texture on one side of the face.’
Dr Jean-Louis Sebagh, a private London-based dermatologist, says he sees examples of ‘screen face’ in his ‘younger patients, the selfie generation’. He points to his own research in 2013 and 2014 exposing artificial skin cultures to blue light for six to 12 hours — mirroring the amount of time that many of us spend in front of screens each day; this found ‘considerable oxidative damage’ to the skin, through cell ageing, uneven pigmentation and inflammation.
Blue light can penetrate down to the dermis, the deeper layer of skin where collagen and elastin are produced, making skin thinner and more fragile, explains Dr Stefanie Williams, a private London dermatologist.
Dr Andrew Birnie, a consultant dermatologist and skin cancer specialist at the William Harvey and Kent and Canterbury Hospitals, adds: ‘It’s been found that blue light causes a degree of increased pigmentation.
‘In particular, it seems to affect people with olive skin and darker skin tones, more than people with very fair skin.
‘I suspect that the amount of blue light energy coming out of sunlight on a hot sunny day is going to be more than that coming from your phone — but I would think that it’s the chronic exposure from phones that might have an impact.’
Blue light might damage skin by generating ‘free radicals’, explains Dr Emma Wedgeworth, a consultant dermatologist at 41 Harley Street and for the NHS. ‘These are very active molecules which bind to skin and cause significant cellular changes. They affect the way DNA is repaired.’
She points to any potential harm likely to be linked to the ‘amount of time that we are spending on our phones and the fact we are holding them in direct contact with our skin’.
One way to protect against this damage is to wear creams that contain iron oxides, she says. ‘I advise people to use a combination of vitamin C serum which gives antioxidant protection and a broad-spectrum sunscreen that is tinted, with iron oxides, to protect against visible light.’
STEPS TO REDUCE YOUR EXPOSURE
USE a blue light filter on your phone, tablet or computer to shield skin and eyes at night, advises Dr Alejandro Sanchez de Miguel, a postgraduate researcher at the environment and sustainability institute at the University of Exeter.
Apps which filter blue light towards the evening include f.lux for your computer and phone. Others such as Twilight or the ‘night mode’ setting on your device will reduce blue light emitted at any time.
EVERYONE should wear factor 50 suncream with five-star broad spectrum protection, to block UVA and UVB light, as well as iron oxides, which protect against blue light, says Dr Alan Birnie, a consultant dermatologist and skin cancer specialist at the William Harvey and Kent and Canterbury Hospitals.
VITAMIN C serums can also provide antioxidant protection against blue light, says consultant dermatologist Dr Emma Wedgeworth.
AVOID using your phone or PC in the dark, as your pupils will dilate and take in more blue light, says Dr Ajith Karunarathne, an assistant professor in the University of Toledo’s department of chemistry and biochemistry.