Screen time and blue light

Screen Time & Blue Light – ‘Getting the Blues’

Blue light

Technology has delivered an astounding array of developments over recent decades. Computers have moved from room sized arrays to, quite literally, the palm of our hands and the interface between the device and us, the screen, is becoming the source of greater scrutiny.

In order to deliver better results for clarity and brightness, technology developers have created screens and lighting that produces a ‘whiter’ or ‘cooler’ light. Consequently we are experiencing a somewhat greater level of blue light from our devices than previously and at greater intensities.

While there is evidence that blue light wavelengths are valuable for increasing our attention span and alertness, it seems counterintuitive to want this effect at night when we are preparing for bed. Yet this is the time when many people tuck themselves in to catch up on emails, surf the web or wander through social media. Put in context, we have now started stimulating our brains at the very point when we would traditionally be winding down for sleep.

Screen time

In Australia there has been considerable interest in how blue light works with the human eye[i]. Recent debate has centred on the role of blue light in macular degeneration and damage to the retina with limited results available thus far. Early indications are that, like UV exposure, the effect of blue light on the eye may be cumulative so damage may appear as a result of a lifetime of exposure rather than from brief periods. When considered in the context of extended screen usage in the evenings as well as all day at work then it is possible to see the source of concern among researchers and industry.

Melatonin & sleep

Research from Harvard Medical School has suggested another link between excessive blue light exposure at night and adverse health effects[ii]. By exposing subjects to light it is possible to change the production of melatonin in the body, which in turn can influence the circadian rhythms (or sleep patterns). The Harvard studies indicate that blue light specifically has a greater effect than other wavelengths or even white light. By comparing blue and green light they found that blue light changed sleep patterns by twice as much (3 hours vs 1.5 hours shift in sleep pattern).

While the dose of blue light from a screen pales when compared to natural sources like the sun there is the timing of the exposure to consider, we have shifted our exposure to include all hours of the day and night rather than just daylight hours. In light of this it appears that prudence is the order of the day so the following tips may prove useful:

  • Use features such as “Night Shift” or “f.lux” which change the type of light (also known as temperature) to a warmer light at night.
  • Consider using warm colour light globes.
  • Many lens manufacturers are offering lens coatings that are specifically designed for screen users such as the Solitaire Protect Balance. These coatings can give relief for people using screens for extended periods.

[i]Blue Light Guidelines Coming’, Optometry Australia News, Helen Carter, June 20, 2016

[ii] ‘Blue Light Has A Dark Side’, Harvard Health Letter, September 2, 2015