Most of us spend quite a lot of time in front of devices, be it laptops, computers or TVs, and smartphones. In fact, as per a report by app analytics firm App Annie, in 2021, Indians spent an average of 4.7 hours a day on mobile phones, compared to 3.7 hours in 2019. Notably, the Covid pandemic had a considerable role to play here. It’s a known fact that excess screen time has a damaging impact on the eyes. However, the blue light emanating from them is harmful to other aspects of health too.
Blue light, part of the visible light spectrum that humans can see, “has the shortest wavelengths and therefore the highest energy”, says Dr Sudipto Pakrasi, chairman – ophthalmology at Medanta Hospital. Although natural and a part of the sunlight, it is also emanated by various gadgets such as TVs, laptops, smartphones, tablets, gaming devices, etc, which constitute the artificial sources of blue light.
“Blue light emitted by electronic devices has been linked to a host of eye-related issues such as cataracts, macular degeneration, dry eyes, blurred vision, and eyestrain,” says Dr Rishi Bhardwaj, HOD – ophthalmology, Paras Hospitals, Gurugram.
“Prolonged exposure also has a cumulative effect and worsens visual fatigue and near-sightedness,” says Dr Shailja Tibrewal from Dr Shroff’s Charity Eye Hospital, New Delhi. “Blue light may aggravate dry eyes and hasten age-related macular degeneration (ARMD). This could lead to loss of vision in the eyes. What is concerning is that while the harmful UV rays are emitted by the sun, blue light is emitted from both sun and light-emitting gadgets and LEDs,” she adds.
On retinal and macular degeneration, Dr Pakrasi says blue light toxicity can lead to that but genetically predisposed are at a greater risk. Explaining the eye disease, the doctor says macular degeneration causes vision loss at the center of the field of vision. “The dry macular degeneration causes the center of the retina to deteriorate, while the wet one causes leaky blood vessels to grow beneath the retina, resulting in blurry vision and permanent eye damage,” he adds. Apart from these, one tends to blink less often when in front of a screen, which further adds to the ills.
According to Dr Bhardwaj, children might be at a greater risk of the blue light damaging their eyes as it is not filtered as well by a child’s eyes as it is by adults.
“During the Covid pandemic, due to overexposure to digital devices, children complained of several eye problems like dry eyes, watery eyes, myopia progression, pain in the eyes, as well as loss of circadian rhythm and disturbed sleep pattern,” says Dr Tibrewal , adding: “Apart from children, anyone who uses digital devices for 4-5 hours per day is at risk. Additionally, the effects of the same are additive, which means that over time, it will only add and increase and can cause photochemical damage, free radical generation in the retina, and further leading to disturbed and damaged vision. The earlier a person is exposed to excessive blue light, the greater the damage in later life.”
Do you know that late-night screentime is disrupting your sleep? “Not only eyes, but the blue light also causes a lot of sleep dysfunction,” says Dr Pakrasi, adding: “It does so by slowing the release of the hormone melatonin, responsible for sleep, thus affecting sleep, causing eye strain, fatigue , headache, sleep deprivation, confusion, and so on.”
“Studies report a negative association between blue light exposure at night and subjective sleep quality,” says Dr Jitender Jakhar, consultant psychiatrist, Fortis Hospital, Vasant Kunj, New Delhi.
It is to be noted here that any light can disrupt sleep by suppressing melatonin secretion, but the harm is more prominent in the case of blue light. A group of Harvard researchers compared the effects of 6.5 hours of exposure to blue light vs green light of comparable brightness. They found that the blue light suppressed melatonin for about twice as long as the green light, thus impacting sleep more.
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“Sleep and mental health share a bidirectional relationship,” explains Dr. Jakhar. Predominantly, by influencing the sleep cycle, the blue light can indirectly predispose an individual to emotional distress. Hence, sleep disturbance can be a prodrome symptom of mental illness,” he says. “Prolonged exposure can also increase the stress hormone cortisol level and make an individual more irritable and anxious,” he adds.
The damaging impact of over-exposure to blue light does not stop here. As it affects sleep, causing sleep deprivation, confusion, fatigue, and headache, the worsening of which may also contribute to the onset of other conditions such as high blood pressure, diabetes, psychotic issues, and have a significant link with depression and mental health issues; and in severe cases, it has been linked to cancers such as prostate, colorectal, and breast cancer, explains Dr Pakrasi. In children, it may also “increase their risk of obesity and attention deficit disorders,” says Dr Bhardwaj.
Speaking on the risk of cancers, Dr Jakhar explains, “The blue light exposure at night and circadian rhythm disturbances are associated with increased risk of hormone-dependent cancers. Both prostate and breast cancer risk are positively correlated with exposure to blue light enriched spectrum. There have been few studies that have reported that artificial blue light exposure increases the risk of prostate cancer by 1.5 times.”
It does not stop here but also accelerates the natural aging process as continuous exposure to the light emitted by these devices increases the oxidative stress within the body and initiates biochemical change within cells, resulting in the production of reactive oxygen intermediate, which leads to necrosis and apoptosis, which are the cardinal causes for aging, the doctor explains.
, day-time exposure to blue light has health benefits as it “boosts alertness, memory and brain function, and elevates mood,” the doctors say. “It regulates the body’s natural wake and sleep cycle, or circadian rhythm. Blue light exposure during the daytime hours aids in the maintenance of a healthy circadian rhythm,” Dr Pakrasi says. However, a large part of this revolves around sunlight, and the same emitted by gadgets during nighttime can have the opposite effect.
“We advise people to use their devices as little as possible,” says Dr Tibrewal. “The hours may differ between children and adults. For example, for children, we recommend a maximum of 2 hours on gadgets,” she recommends.
Here’s what the doctors recommendfor kids
- Limit the use of devices
- Tell them to put away any portable gaming devices at least 30 minutes before bed time
- Turn on the blue light filters of the electronic devices. Many laptops and smartphones come with blue light filters in their software that change the color of the screen to yellow, which is soothing to the eyes and prevents blue light-induced damage
- Use blue-blocking glasses or an app that filters the blue/green wavelength if you work the night shift or spend a lot of time using gadgets at night
- Take 15-20 minutes of break after every task if your job demands excessive screen time
- Follow the 20-20-20 rule in which you focus on an object 20 feet away for 20 seconds after working on a screen every 20 minutes
- Blink frequently to avoid dry eyes