How Blue Light Affects Our Health

This was taken from the excellent Consumer Friendly Version of the Whitepaper by Occushield. Go get all of your blue light-blocking gear from Occushield and use the coupon code WARRIORWELLNESS15 FOR 15% OFF YOUR ORDER!

Light can be represented as a wave, part of the continuous electromagnetic radiation (EMR) spectrum (above). We all know X-rays and ultraviolet (UV) radiation are very dangerous. As you can see in the diagram, blue light (380 - 500 nm, which includes violet and blue) is very close to these hazardous types of waves. A misconception is that there’s a magic cut-off once you pass from UV into the visible spectrum of light. However, light is continuous; there is still danger in the kinds of light you can see. The further left you get along the spectrum (the bluer you go!), the smaller the gaps between the waves become, because these waves have shorter wavelengths. Short wavelengths of light carry more energy because they vibrate faster. Why are shorter wavelengths harmful? Short-wavelength light causes photochemical damage to cells and their DNA. So, every time you are exposed to blue light your cells/tissues are at risk of being damaged. Every minute you spend exposing your eyes to blue light increases the chances that you will do damage to your eye. So, you either need to decrease the time spent being exposed to blue light, or reduce the intensity of the blue light.

Light between 380-500 nm is the blue part of the spectrum. It is thought that this part of the spectrum may contribute towards visual stress, eye strain and headaches. Harmful Blue Light between 380-455 nm is known as high energy visible (HEV) light. This is the blue light that can cause photochemical damage, eventually leading to cell death and induce retinal damage in the eye. Helpful Blue Light between 455-500 nm is the part of the spectrum that supports our sleep/ wake cycle. If we are exposed to helpful blue light when we first wake up it helps set our internal clock and can help us to be more alert throughout the day and get a better night’s sleep. Conversely, if we are exposed to too much blue light before going to bed it can make it difficult to fall asleep.

Even though LEDs and digital devices are not as bright as the sun, they still emit photons of light with the same wavelengths (energy). And those photons can cause photochemical damage to the cells in your retina no matter how intense the source is. If there are fewer photons (less intense) the probability of damage is lower and that just means it takes longer for the damage to accumulate. However, many of us spend an awful lot of time on digital devices.

Measurements of absolute intensity show that a 20 minute walk on a beach looking at reflected sunlight outdoors = 133 hours (5.5 days!) of looking at your phone. However, you wouldn’t stand in bright sunlight on a beach without sunglasses for 5 minutes, let alone 20 minutes. Numerous research studies highlight the benefits to health and wellbeing when blue light is reduced.

Technology is getting brighter and we should be careful going forward. It’s better to take a precautionary approach and limit our exposure to light. Prevention is always better than cure.

Reducing exposure by reducing either intensity or time can decrease the risk of retinal damage through life. Here are some steps you can take: Use technology that filters out harmful blue light Devices that filter out some of the blue light (screen filters, sunglasses, photochromics and blue filtering lenses in glasses, contacts and intraocular lens replacements) can reduce blue light reaching the retina. Choose your light sources wisely Using light sources (bulbs and screen settings) with lower kelvin rating e.g. 2700K will reduce the amount of blue light in your home and work environment. Eat an eye-loving diet Improving your natural protection (macular pigment density) by eating more dark and brightly coloured vegetables and fruits can reduce blue light reaching the central retina (macula). Most importantly, reduce blue light! Reducing blue light decreases the light that is scattered most, decreasing glare and increasing contrast, thereby improving image quality and reducing eye fatigue.

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