We wake up to our mobile screens, switching off a trilling alarm, checking our notifications; at work, it is at least eight hours in front of the computer; back home in the evening, it’s time for TV. With the pandemic, even socialising had shifted to the digital space.
Our world is now always bathed in bright, blue light, wreaking havoc on our sleep cycles that depend on night’s darkness for routine.
But, why does blue light specifically pose a risk?
For your eyes, blue light is sunlight
“Blue light refers to a part of visible light of the electromagnetic spectrum, which falls between the 400 to 490 nanometer wavelength,” says Dr. Soman Sukumaran Nair, specialist ophthalmologist at Zulekha Hospital, Dubai.
It’s actually strongest in sunlight and is what makes the sky blue. For indoors - LED light, used to illuminate everything from our mobiles and TVs to our homes, emits blue light. According to a 2011 study published in the US-based Journal Applied Physics Letters, white LEDs also actually degrade as time passes, with increasing blue light emission.
How does it affect us?
1. It wakes you up
Within our eyes, there is a special set of cells that call the shots on melatonin – your sleep hormone. They are called photosensitive retinal ganglion cells, housed in the innermost layer of the retina and contain the chemical, melanopsin, explains Dr Nair. He says, “This is responsible for regulation of melatonin by the pineal gland, which is inside the brain.”
According to a 2005 study published in Chronobiology International, official journal of the International Society of Chronobiology, melanopsin is activated most efficiently to suppress your sleep hormone by blue light between 420 and 440 nm.
Dr Sindhu Kumari, ophthalmologist at Al Kamal Medical Centre, Abu Dhabi, says, “During the day, blue light wakes you up and stimulates you.” It is known to boost memory, attention span, reaction times, cognitive performance, and reaction time during the day, according to a 2015 study published in online open-access journal, Procedia Manufacturing.
2. Reduced sleep quality and duration
This backfires during the night.
Dr Kumari says, “When you are using screens or digital devices in the night, the body reacts to it as if it is being exposed to sunlight. Your brain is confused actually – it stops producing the sleep hormone, known as melatonin, and you end up not getting enough sleep. It affects our sleep-wake cycle.”
When you are using screens or digital devices in the night, the body reacts to it as if it is being exposed to sunlight. Your brain is confused actually – it stops producing the sleep hormone, known as melatonin, and you end up not getting enough sleep. It affects our sleep-wake cycle.
The effects include reduced sleep quality, duration and waking up during the night, explains Dr Nair: ”In fact, I have so many patients here who tell us that there is a lot of early morning tiredness and fatigue. When you have reduced sleep, there are going to be multiple disorders the commonest of which are mood disorders, fatigue, headache, heavy eyes, lethargy and in some cases, even depression.”
Dr Vinod Gauba, ophthalmologist at Imperial Healthcare, Dubai, adds, “Overexposure to blue light can cause restlessness and insomnia. In one study, as little as 2 hours of exposure to blue light at night slowed or stopped release of the sleep hormone melatonin.”
Does blue light damage our eyes, though?
As of now, no. Dr Kumari says, “There is no studies that have shown that blue light from screens causes any damage to the eyes."
“It is known that excessive exposure to blue light can lead to macular degeneration, which is theoretically linked to age related macular degeneration and age related macular dystrophies,” says Dr Nair. However, according to a 2016 study in Eye, the official journal of the UK Royal College of Ophthalmologists, extended blue light from devices is lower than natural exposure from sunlight even on a cloudy winter day in the UK.
Nevertheless, Dr Nair adds that since our screen use has increased dramatically in the past decade and half, it will take more long-term population studies to fully understand the impact on our eye health. He says, “The harmful effects of blue light may be much more than this, but the effect of these will only be very clear when time passes as we get more data.”
To block or not to block
Photochromic lenses that turn dark in sunlight or blue light blocking glasses that are designed to filter out harmful blue-violet light from digital screens are options to reduce your exposure. Do you need them?
“To date there is lack of consistent evidence for the larger scale introduction of blue light blocking lenses in routine,” says Dr Kumari. She references one 2017 study by the City University of London published in the journal Ophthalmic and Physiological Optics, that reviewed other studies and found a lack of any conclusive evidence on the benefits of blue-light blocking glasses for visual performance, sleep quality, eye fatigue or macular health.
If you ask me - can I watch a movie on Netflix for say, two hours in the night wearing a blue-light blocking lens? Will I be okay in the morning? Of course, you will not be okay in the morning – because you are just solving a small part of the problem.
Dr Nair says it could increase your general eye comfort, especially if you already wear glasses: ”If you need to wear glasses, then having blue light protection would certainly improve the quality of your vision and would reduce the symptoms and effects.”
But, regarding the question that’s on all our minds – “If you tell me - can I watch a movie on Netflix for say, two hours in the night wearing a blue-light blocking lens? Will I be okay in the morning? Of course, you will not be okay in the morning – because you are just solving a small part of the problem,” says Dr Nair.
The real culprit is Digital Eye Strain
Computer Vision syndrome or Digital Eye Strain is the umbrella term for all the problems that happen in our eyes, as a result of our daily screentime. This includes tired, red eyes, developing short-sightedness or refractive errors, ocular allergies and more – and reasons include close focus, lack of blinking.
“70 per cent of patients in our OPD (outpatient department) actually complained of digital eye strain. Blue light exposure is only a part of it – what is more important is the amount of time you spend in front of the screen,” says Dr Nair.
According to Dr Gauba, some DES symptoms are:
• Dry eyes
• Sore or irritated eyes
• Tired eyes
• Headaches
• Facial muscles fatigued by squinting
The average person with internet worldwide spends around 7 hours looking at the screen every day, according to a 2021 report by Data Reportal, a digital insights and trends company.
So, what can we do to reduce these effects when screens are so necessary for our daily life?
Keeping away the blues
In summary, using blue-light blocking glasses does not mean you will avoid the harmful effects of using mobile devices and screens, but these tips can help:
1. Minimise your unnecessary screen time
Difficult, but simply pressing pause on scrolling, and looking away is the first advice that Dr Nair gives. “We tell our parents of children to tell them to put an alarm on the mobile screen and restrict to particular periods of time,” says Dr Kumari. There are also apps you can use to monitor and control your screen time.
2. Use ‘night mode’ on your screens
“If you’re so busy working that you have to use digital devices, you can shift it into the night mode, ” says Dr Kumari.
3. Stop looking at screens for at least one hour before sleep
“Set a limit of turning off your devices at least one hour before bedtime and charge your devices in a different room so you are not tempted to turn them back on,” says Dr Gauba.
4. Use an anti-glare coating on your glasses and screens
Dr Nair says, “Anti-reflective coating basically works with the principle of destructive interference… it not only helps you in front of a screen, but also helps you when you’re driving for example, by reducing the glare from headlights.”
According to Dr Kumari, using matte screens can also reduce glare, increase contrast and reduce eye strain.
5. Blink, blink, blink
“One reason that we are more susceptible to dry eye when using electronics is that our blink rate is reduced significantly. Put a sticky note on your computer screen that says 'Blink!', as blinking more often will keep your eyes moist and refreshed,” says Dr Gauba.
One reason that we are more susceptible to dry eye when using electronics is that our blink rate is reduced significantly. Put a sticky note on your computer screen that says 'Blink!', as blinking more often will keep your eyes moist and refreshed
6. Sit at an arm’s length from your screen
“You have to position yourself 25 inches or an arm's length away and preferably the screen should be a little lower so that your gaze is shifted downwards so that your eye doesn't become dry because your cornea is less exposed and covered by your lids, ” says Dr Kumari.
7. Don’t use screens in the dark
“When you are using screens in the dark, your pupil is more dilated and more amount of light goes it the eye, producing disturbance and discomfort for the eyes,” explains Dr Kumari.
8. 20-20-20 rule
“Every 20 minutes, shift your eyes to look at an object at least 20 feet away for at least 20 seconds,” says Dr Gauba. If you are near a window, Dr Nair recommends looking out at the view during your break to shift your eye’s focus to faraway objects.
9. Use red lighting at night
As per Harvard Health, it is recommended to use dim red lights for night lights as red light is less likely to reduce melatonin and shift your Circadian or sleep-wake rhythm.
