Blue light has a downside?

What is blue light? What effects does blue light have on our sleep patterns and our health?

Strong persistent headaches, tired, dry eyes, blurry or double vision…sound familiar? Ever since we started working from home, I have been struggling with these symptoms. Inadequate lighting, work station, working in bed, working late at night, have all contributed to the problem. I’m sure many of you will agree with me. We can all benefit, however, from greater eye care awareness in this digital age. The working from home bit is not going to change anytime soon, so there is no chance of simply eliminating the culprit. Establishing good habits as early as possible is the best solution.

What is blue light?

Not all colours on the light spectrum have the same effect. Blue wavelengths, which are beneficial during daylight hours because they boost attention, reaction times and mood, seem to be the most disruptive at night. Moreover, the proliferation of electronic devices with screens, as well as energy-efficient lighting, is increasing our exposure to blue wavelengths, especially in the evenings.

So what does that mean? At night, the longer the wavelength of the light, the fewer negative effects there will be on your eyes. Red, orange, yellow and green, above 550nm, will have a less negative impact not just on your  eyes but also on your overall health. However, light with a lower wavelength, below 500nm, will damage eye health and affect the hormonal balance of your body.

In order to understand how the different light affects your eye health and how you actually see these different colours, you will need to know how your eyesight actually works.

Cross section through a human eye, schematic view of the retina including rod and cone light receptors (adapted from Encyclopaedia Britannica)

The elements of the inner eye that allow you to see colours are called photoreceptors. There are four types of photoreceptors in the human eye, 3 types of cone cells, green, red & blue, that allow you to see colour in daylight. The rods on the other hand allow you to see at night without any colour.

How does light affect your sleep and your health?

Although it is environmentally friendly, blue light can affect your sleep and potentially cause disease. Until the arrival of artificial lighting, the sun was the major source of lighting, and people spent their evenings in (relative) darkness. Now, in much of the world, evenings are illuminated, and we take our easy access to all those lumens pretty much for granted.

Most of the evidence we have nowadays regarding the way blue light affects your health comes to us through research on your biological clock, otherwise known as the circadian rhythm. At night, blue light throws the body’s biological clock out of sync. Sleep deprivation may be the cause of diseases such as cancer, diabetes, heart disease, and obesity.

Everyone has slightly different circadian rhythms, but the average length is 24 1/4 hours. The circadian rhythm of people who stay up late is slightly longer, while the rhythms of earlier birds fall short of 24 hours. Dr. Charles Czeisler of Harvard Medical School (a must read), showed in 1981 that daylight keeps a person’s internal clock aligned with the environment.

Researchers from Harvard Public Health Institute have conducted an experiment measuring the effects that different lights have on our sleeping patterns. What this study found is that the blue light suppresses melatonin almost twice as much as green light. It also shifted the Circadian rhythm twice as much in comparison with green light, on average 3 hours to 1.5 hours.

Most of us these days work from home and late at night, exposing ourselves to the damaging effects of the blue light from our electronic devices. This directly affects the quality of your sleep and with that come the health problems. Blue light has not, however, been linked directly to eyesight issues such as eye strain, also known as computer vision syndrome. This happens when we spend long hours working on computers, staring at screens or our mobile devices. According to Dr.Mike, the reason why this occurs is that intense staring at screens for a prolonged period of time results in the eye muscle becoming fatigued. This causes a stinging, burning sensation in your eyes, something with which I am very familiar as I prefer to work at night.

The Peniel Gland and the secretion of Melatonin – sleep hormone

What we know for sure is that Blue Light actually suppresses Melatonin. Melatonin is a critical hormone produced by the pineal gland in the absence of light stimulation. This hormone is responsible for inducing a state of sleep and regulating circadian rhythms that govern our sleep-wake cycle. Melatonin is also known as the repair hormone. A healthy sleep pattern and cycle is one of the most effective practices to optimise health and maximise daily energy, function and performance.

Is blue light at night harmful to children and young adults?

According to a survey by the Pew Research Center, 95 percent of teens have access to a Smartphone and 45 percent say they are online almost constantly. A separate survey from 2015 revealed that a staggering 97 percent of all teens play video games. So between social media, homework and video games your child is probably spending quite a bit of time in front of a digital device. Although blue light from digital devices isn’t as harmful as it’s made out to be, Digital Eye Strain is something to be wary of. If your child spends hours at a time playing video games, browsing social media sites or even just working on school-related projects and homework, they may already be suffering symptoms of Digital Eye Strain.

What Dr Mike (on his YouTube channel), suggests to combat eye fatigue is :

• Stand at least 2 feet away from your screen,
• Use lubricating eye drops,
• Implement the 20/20/20 rule. What this actually means is, every 20 minutes; stare at a point approximately 20 feet away from you for approximately 20 seconds. This will allow your eyes to relax and to regain focus.

According to Dr. Daniel Lewis, from The Lewis Institute for health & wellbeing, the 5 most important steps to do, to increase the natural secretion of melatonin are:

Go to Sleep Early: Be in bed by 10PM. Hormone secretion, body temperature, digestion and tissue restoration are governed by 24 hour cycles (circadian rhythm) linked to natural light exposure. Up to 80% of melatonin secretion takes place between the hours of 11pm and 1am. Individuals who are in bed by 10pm are maximising the ability of this restorative hormone to heal and regenerate body tissues.

Practice intentional quiet time before you go to bed: Meditation helps boost melatonin. This process reduces the time taken from lying down to falling asleep and boosts the quality and benefits of the sleep. Take 20-30 minutes before bed and relax your mind and concentrate on your breathing. I personally include evening and morning meditation as part of my daily routine. I also use the help of mindfulness apps like Headspace, Calm & Breathe, Meditation & Sleep

Reduce sugar, artificial flavorings & preservatives, processed foods, caffeine and any other sort of stimulant: All these stimulants reduce melatonin and growth hormone secretion in the body.

Hydrate effectively: Dehydration causes chronic stress responses in the body that minimize healthy melatonin and growth hormone secretion.

Keep your bedroom as dark as it can be. Any sort of light after 22:00 will prevent the pineal gland from forming melatonin. This will of course cause sleep deprivation and prevent the body self-regenerating.

Can Blue light be filtered with glasses?

Eye ergonomics

Yes. There are many ways to filter or reduce the amount of blue light. Glasses are just one option. If you choose to use such filters it is best to use them during late evening hours. Don’t forget, wearing blue filter glasses during the day will be counter-productive, as our brain uses daylight (blue light) to maintain our Circadian Rhythm and tells our body that it is time to be awake and be active. Researchers from the University of Toronto, Canada, conducted studies on effective blue light filter glasses. They studied two groups of test subjects… the first, exposed to bright light wearing blue light filter glasses and the second group, exposed to mellow, dimmed lights without glasses. They discovered that their melatonin levels were the same, strengthening the theory that blue light filter glasses actually work.

I started using blue light blocking glasses a few months ago on a suggestion from a friend and I must say that my headaches and tiredness have gone and my sleep quality has improved significantly.

Now don’t forget blue light blocking glass will not prevent digital eye strain. For prevention and treatment follow the 3 simple steps that Dr. Mike and many prominent ophthalmologists suggest:

• Stand at least two feet away from your screen
• Use lubricating eye drops
• Implement the 20/20/20 rule. Every 20 minutes, stare at a point approximately 20 feet away from you for about 20 seconds. This will allow your eyes to relax and to regain your focus.
• If you have to work evenings and late and night use blue light blocking glasses.

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