Apple move ‘acknowledges blue light dangers’

Apple's addition of a blue-light reduction feature into an update to its operating system is the first acknowledgement by a major manufacturer that blue light can be a health hazard.

The latest update of its operating system, iOS9.3, includes a night-time screen mode with reduced intensity in the blue part of the visible spectrum. The move will be seen as an endorsement of those who have been arguing that the health issues of blue light need to be addressed by industry.

It’s long been known that blue light or, to be more accurate, the quantity of blue within the white light spectrum, helps to suppress the production of the sleep hormone melatonin. Exposure to light at night has been linked to conditions like cancers, diabetes, heart disease and obesity – and while the jury is still out on how blue light can trigger these disorders, its deleterious effect on health is well established.

A recent Harvard Medical School Health Letter claimed: ‘light at night is bad for your health, and exposure to blue light emitted by electronics and energy-efficient lightbulbs may be especially so’.

LED lighting has a pronounced spike in the blue part of the spectrum, as the vast majority of white LED lighting is the result of a conversion of pure blue light using phosphors.

The European Commission-funded Lighting for People, a web-based platform of research on solid-state lighting in Europe, has published recommendations for lighting at home, which include:

Provide lighting that is cool in appearance and at higher levels during the daytime, but shift to warmer light at a lower illumination level in the evening.
Applying the positive nature of blue-enriched light, provide higher lighting levels in workplaces to improve alertness.
Excessive use of tablets and computer screens in the evening will delay sleepiness.
Have warm, low level illumination at home in the evening and refrain from using blue-enriched screens during that time.

There are already examples of installations featuring so-called circadian lighting, where the colour and intensity of light varies thoughout the day to match our natural rhythms. At the professional end, lighting companies are investigating wireless lighting solutions, based on LEDs capable of shifting their white light from cool to warm depending on the time of day. And at the consumer end of things there are a number of lamps coming on stream that claim to support the circadian rhythm, either by shifting their colour temperature, or because they are aimed directly at the late-night lighting market.

A recent installation at Kongsgardmoen School at Kongberg, in Norway, is designed to assist teachers in their interaction with students by giving them the ability to change the tone of the lighting depending on the class activity. Early reports suggest that students are reacting positively to the new lighting, with improved concentration and behavior throughout the day.

But established metrics remain elusive. Practitioners say hard data is needed to create a standard for what circadian lighting should look like from a technical standpoint. Typically, the lighting industry delivers product within the capability of current technology and the developments around the LED revolution has brought this topic into a sharper focus.

  • Internet of Things-based lighting control, data capture and security will be a key theme of LuxLive 2017, which takes place on Wednesday 15 November and Thursday 16 November at ExCeL London. For more information, and to register for free, click here.

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Comments 9

This pronouncement is just what I would expect from Harvard, where it seems that they believe themselves to be so very much smarter than the rest of the world. Did it ever come into their minds that perhaps some of us would choose to not have sleep oriented lighting? That some of us may possibly WANT to be awake a bit longer than them? Some of us may, in fact, have reasons to want to stay awake and alert during the hours of darkness. Why in the world should we be treated like mentally challenged folks just because we choose to have a more stimulating spectrum of illumination.

In agreeing with Dieter and Ian, I'd like to add that the International Dark Sky Association identified the excessive blue emissions of most LEDs (relative to the balance of the spectrum) and their narrow bandwidth in 2009, and noted then that those emissions appeared to fall at or near the peak response of the IPRG cells. IDA's 2010 white paper, still available on its website, continues to be proven as industry slowly accepts this fact. IDA undertook its actions because it seems crazy to employ outdoor light sources with exactly the wrong spectrum, as it not only affects humans but all living beings. Removing blue from the output of screens at night was hardly invented by Apple. I would also suggest readers download the CIE white paper from the summer of 2015 that, while recognizing the potential of using light and spectrum for possible human benefit, states clearly that it is presently "impossible" to apply these methods for general audiences. What they mean is that blue light should not be used as a stimulant or therapy for office buildings, schools, etc. It should only be used under medical supervision for specific individuals at this time. Committees are hard at work in developing protocols for general population use and results are hoped for by 2017. In the meantime, lighting designers should probably avoid employing any exaggerated spectral tuning with the promise of enhanced productivity or any other benefit. In fact, at this time the only scientifically supported light source and method to provide human benefits to general audiences is natural daylight. If you study the spectrum of natural daylight at any color temperature that actually occurs naturally, you will find that in addition to wide-band blue, there is more-or-less a similar amount of broad band light at every color. Using narrow band sources like LED or fluorescent with little or no long wave red may turn out to be a mistake that creates new problems. Because the best scientists in the world on the subject are on the CIE committees, it would be wise for designers and manufacturers to wait until protocols of practice are established and instead, emphasize the use of what nature already provides for free.

What Ian Ashdown said ;-) I have been using f.lux on my computer, and "Twighlight" on my Android phone, for quite a long time... this certainly not some new, exciting Apple invention! BTW, I think sunlight has about 1000x the amount of 'blue light' that my mobile emits?

> Apple's addition of a blue-light reduction feature into an update to its operating system is the first > acknowledgement by a major manufacturer that blue light can be a health hazard. > No, Apple has acknowledged a marketing opportunity for its products, as established by the f.lux product it quashed. It has not, to my knowledge, specified any particular peer-reviewed studies relating to health hazards associated with blue-rich light. The studies referenced above are all over the map. The "recent Harvard Medical School Health Letter," for example, is an anonymously-written 2012 press release titled "Blue light has a dark side," that uses out-of-context quotes from unreferenced studies. I agree with Dieter's comments above, with the additional observation that Apple sells products; it is not in the business of validating medical studies.

Thank you for rephrasing the headline and avoiding the term "blue light hazard"

I have been using the f.lux software to deal with this excessive 'blue light' issue for several years. Take a look at

Dieter you are indeed correct - it's best to distinguish between 'blue light hazard' which has come to mean something different - ie potential retinal damage - from the disturbances that blue light can create via melatonin, therefore we have amended the headline today.

Good to see that iOS9.3 has eventually realized a feature that has only been available for non-iOS systems so far, e.g. by the f.lux program for PCs. It is essential to prevent nocturnal exposure to blue-rich light in order to prevent disruption of melatonin secretion and related negative consequences on sleep quality. Detailed insights in this matter which help to understand the background how light affects humans are given by scientific assessments which are available on the website. Even if I agree to the article in general, i'd like to point out an error in the headline: The effect of blue light at night on melatonin secretion and on disturbed sleep is different to what is called "blue light hazard". The term "blue light hazard" is related to a potential photobiological risk of injuries to the retina which can be caused by extreme bright light sources. This can happen when directly gazing to the sun for some seconds or to extremely bright high intensity discharge lamps. But the intensity of a display on a mobile device is less than a few percent of what could possibly be a risk for retinal damages even under worst conditions and with long exposure times. In the discussion of potential risks the different effects should clearly be differentiated in order to avoid confusion.

My kindle fire tablet added this in the latest update a few weeks back

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