Why blue light is bad for your eyes

Does your typical day sound like this? Wake up, turn on your laptop for a quick virtual sweat sesh before supervising your kids' online classes all morning. Are your afternoons filled with Zoom meetings and evenings with Netflix? And yes, let us not forget the Whatsapp texts that stream steadily into your phone all day that you keep looking at and responding to (or not, I'm not judging you). 

Multiple surveys indicate that screen time has gone up drastically--by over 50%--since covid unfurled across the world in early 2020. And screens, as we all know, all use LED technologies which emit very high amounts of blue light. But, according to Dr Nusrat Hakim, a consultant ophthalmologist and refractive surgeon, Masina Hospital, Mumbai, the short-wavelength natural light and the light emitting from the digital screen are the primary sources of blue light exposure.

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It isn't the blue light is intrinsically evil: numerous studies have suggested that blue light plays a role in promoting alertness, memory and cognition, says Dr Hakim, adding that it also is believed to stimulate the secretion of melatonin which helps regulate circadian rhythm or sleeping patterns. However, an excessive amount of blue light exposure poses a potential threat to overall well-being, she says. "Studies have suggested that excessive exposure to blue light during the night stimulates the brain to inhibit melatonin secretion and increase corticosteroid thereby disturbing the hormonal secretion which has a direct effect on one's quality of sleep," says Dr Hakim. 

It isn't just about sleep, of course. Dr Hakim points out that overexposure to blue light also causes oxidative changes in the corneal epithelium cells, leading to the formation of dry eyes. It also impacts the retina and lens of the eye and is capable of causing permanent damage to them, she says. However, not all is lost. While obviously, you can't stop looking at screens altogether, here are some minor lifestyle changes you can make to reduce the adverse effects of blue light

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1. Yes, you may have to cut down on your screen time. Or at least take regular breaks from it every twenty to thirty minutes. And keep blinking. 
2. Avoid screens at night. No, you don't need Netflix to go to sleep; you can read a book or listen to some music instead.
3. Try using computer glasses, those special ones with yellow filters that can help ease the strain on your eyes.
4. Use a filter on your phone or computer; also, make it a point to switch to night mode close to bedtime. Or even better, don't bring devices into your bedroom. 
5.  Don't skip your yearly eye examination. Seriously, prevention is better than cure, remember?