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Blue Light the good and the bad

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. There is a lot of debate about this even among optometrists but what I am going to tell you is what is known. The truth about blue light the good and the bad.

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. Our circadian rhythm affects our sleep, blood pressure and heart rate, hormone secretion, and more. Blue light 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. 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. Then the blue light from your device will not upset your natural body clock. You could even wear blue blog glasses but please only during night hours.

Conclusion on blue light the good and the bad.

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.

Myths about blue light. – As seen on many websites by those with no experience in optics.

  • Short-wavelength, blue light is not as easily focused as it’s focus point is in front of the retina. Wrong. All visible light does transmit all the way to the retina. It does not stop just in front of the retina.

The reason for confusion on blue light.

The main reason blue light receives such a bad reputation is the incorrect classification by some countries in their sunglasses standard. Here in Australia ultraviolet or UV radiation is classified as all rays between 200nm and 400nm. Which is correct. These are known to be harmful to skin and eyes. Violet and blue light start at 400nm and are within the safe visible spectrum.

In the USA and EU their sunglasses standard classify UV radiation from 200nm to 380nm. This is incorrect. The spectrum between 380nm and 400nm was removed from the US and EU sunglasses standards when they copied the Australian sunglasses standard. They believe the sun in their countries is not as bright as it is in Australia. This is true. But now this missing 20nm of harmful UV rays is sometimes confused with High Energy Visible light (HEV – blue light) because it is not correctly classified as harmful UV.

The problem is children between the ages of 0 and 10 years old do transmit these harmful UV rays between 380nm and 400nm all the way to the retina. So true 100% UV protection is a must for everyone but especially young children. You can follow this link and read all about how UV rays damage young eyes.

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 radiation.

Ultraviolet radiation 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 rays. We know that even small amounts of UV rays over time do have an accumulative effect leading to eye diseases such as cataracts, pterygium, actinic & droplet keratites, pinguecula and macular degeneration.

Don’t miss the latest sunglasses “WARNINGS” at the top of the home page. They will save your child’s eyesight. This is updated when we see any problems regarding standards and sunglasses.

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