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Blue Light, good or bad?

Idol Eyes Australia blog – All about sunglasses and eyes


The truth about blue light.

I am continually asked if the blue light emitted from all modern-day LED devices is harmful to our eyes. With so much *miss-information (*mainly from companies and people trying to sell you blue light blocking products or medicines) there is confusion about blue light and there is a lot of debate about this even among optometrists but what I am going to tell you is what is known about blue light.

What is blue light.

Blue light is classed as the wavelengths of light between 420–500nm (nano-meters). This is within the visible spectrum.

visible light spectrum
visible light spectrum

We know that there is 100 times more blue light from the sun than any consumer LED device. The blue light from the sun is extremely beneficial in setting our circadian rhythm or body clock which affects our sleep, blood pressure and heart rate, hormone secretion, and more. It also naturally suppresses the body’s melatonin production which does boost alertness and attention. Evidence is now associating circadian rhythms with eye growth and refractive error development. So it is imperative not to upset your natural body clock.

The trouble with blue light from LED devices.

Some researchers have shown that blue light at 445nm when the energy is 3 μW (micro-watts) or greater can cause cell damage. But this research was done under laboratory conditions, not on actual living tissue like an eye. And in a healthy human, all living tissue is constantly trying to repair itself.  Electronic devices typically emit no greater than 1 μW, and it has not been shown there is any harm or accumulative effect for such low energies.

So the real problem with LED devices is if they are used at night as the blue light can upset your circadian rhythm or body clock. We know for example night shift workers who do not get enough blue light of a day time to set their circadian rhythm correctly, do suffer from ill-health and a shorter life.

So what should you do about blue light.

If you don’t spend much time out doors of a day and are stuck in front of an electronic device then the small amount of blue light being emitted may actually help to set your circadian rhythm but of a night-time I would suggest that you turn off your devices. Yes, I said turn off your devices. And for all of you who just said, “What, are you crazy?” and cannot be without your device of a night then at least turn down the brightness of your display, push the device further away from your face and turn on a warm white light so the blue light from your device will not upset your natural body clock.

Conclusion on blue light.

Blue light does have real known benefits when received at the correct time, daylight hours. And preferable not received at night so you don’t upset your circadian rhythm.

I would not recommend wearing blue block sunglasses during day light hours (unless advised by an optometrist to do so) as you require the suns blue light to set your circadian rhythm, so that you will have a normal healthy life.

What I have stated is based on information we have today and this may change as we gain more information in the future.

The real dangers are from UV light.

Ultraviolet light is well-known to cause many eyes diseases and skin cancer, so protecting your eyes with good quality sunglasses is essential to prevent long-term exposure to UV light. We know that even small amounts of UV light over time do have an accumulative effect leading to eye diseases such as cataracts, pterygium, actinic & droplet keratites, pinguecula and macular degeneration.

Next installment – The real known danger of mobile devices to eyes.