Millions of years ago people lived in sync with nature.

Yes, they were dying somehow every day from fever, but life was good, sort of.

When we lived in caves we didn’t have light bulbs and this somehow helped our circadian clocks to stay on track with the natural day and night cycles of the Sun.

People oriented if it’s day or night by the blue sky and looking at blue light became a major factor for controlling our sleep hormones.

At some point, evolution created one special photoreceptor into the eye. The only function of this photoreceptor was only to check if it’s day or night and tell our brain the result, so our brain can control our biological clocks.

Eye Basics

Our eyes are something like 2 cameras glued to our face.

The sole purpose of our eyes is to focus light on the back of our retina where 2 types of photoreceptors detect the wavelength and the color of the incoming light.

We can look at both distant and closer objects thanks to our biological lenses which change the focus distance we are looking at.

The first type of photoreceptor in our eyes is called

Rods

Our of all photoreceptors in our eye more than 95% are rods.

They are responsible for our night vision and are also really bad at recognizing colors.

Rods are not so sensitive to colors and this is the reason why it’s hard for us to see the color of things when it’s dark.

Cones

Cones are mostly around the center of our retina.

Thanks to cones we can see things in bright light be it sun or artificial lights.

There are 3 types of cones: red, green and blue and thanks to them our eye is awesome and detecting colors and distinguishing things with different colors.

Eye Basics 2.0

Rods and cones were all scientists knew before the beginning of this century.

The common wisdom was that the eye contains only 2 types of photoreceptors responsible for the things we see with our eyes.

Meet Ignacio Provencio. The neuroscientist who in 1998 found new photoreceptor called Melanopsin and for the first time proved that light is not only useful for our vision, but it’s critical for many biological processes.

It turns out that Melanopsin is present in much more mammals and it doesn’t play any role in our vision.

The main role of Melanopsin is to control our biological clock and circadian rhythms.

It does this by detecting when blue light is present in our environment.

Melanopsin activates when blue light enters our eye and it sends a signal to our brain that it’s day and our brains stops the secretion of our sleep hormone melatonin.

Melatonin from his side controls a large number of processes in our bodies and is responsible for our good night sleep.

When we have melatonin in our bodies we feel sleepy and this is the reason why you can’t fall asleep when you sit in front of the computer at night.

Blue light

Blue light comes from everywhere around us. It’s not only the monitors, or the smartphones, or the tablets around us.

Almost all artificial light sources today generate much more than the recommended amount of blue light.

All energy saving products, all LED light bulbs, and screens have a negative impact on our vision and wellbeing.

Years ago when we had only the standard  Incandescent light bulbs things were good, because the light emitted from this lightbulbs is with color temperature around 2800K.

Things were even better when people used only candles which have color temperature around 1800K.

Basically, the lower the color temperature the less blue light the light source emits.

Less color temperature is close to the natural fire found in around us for millions of years.

In contrast, LED light bulbs and monitors both emit around 6500K.

The sky emits more blue light, but the difference is that it’s full spectrum sunlight and this is beneficial for us.

So the problem is not exactly that we get too much blue light. The problem is actually that we get too little of the other light and especially red light.

Iris tries a lot to fix this problem, but you also need some light hygiene.

Even with Iris, if you stay late at night with LED light bulbs ON, you will fall asleep slower and your health will be compromised.

Avoid light at night. If you can’t avoid all light try to avoid blue light.

Health

Sleep is one part of the problem with blue light.

The bigger problem is actually that blue light enters deep into our eyes and it’s high energy light.

You may know that the UV light is really bad for our eyes, but you probably don’t know that the blue light is also a big problem.

We have substance in the skin, hair and eyes called Melanin that absorbs UV light, but blue-violet light continues it’s path to the macula of our eyes.

This, in the long run, causes macular degeneration.

Solutions

As you can guess the best solution is to live in a cave and to get only full spectrum sunlight, but we all know this is impossible.

Try to avoid light at night and if you just can’t avoid all light and need to do some work on your PC use Iris or other blue blocking software.

Iris has Sleep type preset which removes almost all blue light from your screen.

In front of the TV use some blue blocking glasses or just sunglasses. Sunglasses are sometimes even more effective that blue blockers since they also block UV light.

And lastly, remove all LED light bulbs in your home. Although energy efficient they are bad for your sleep. Use the good old incandescent light bulbs or if you can use candles sometimes.

Thank you very much for reading this article.

Final words

If you liked this article share it with friends. You can also try Iris, which is software for eye protection and better sleep.

Iris will automatically make your monitor more healthy by reducing the blue light emitted from your screen at night and much more.

Blue light at night stops the secretion of our sleep hormone melatonin and this prevents us from getting the so desired good night sleep.