Blue light unhealthy?

[Alfred001]

I've seen some talk of blue light being bad for eyes and the circadian rhythm and it all, based on nothing but intuition, felt like bunk with no scientific backing.

Is there actually any legitimate science behind this?

[StringJunky]

Quote

Effects of blue light on the circadian system and eye physiology

Abstract
Light-emitting diodes (LEDs) have been used to provide illumination in industrial and commercial environments. LEDs are also used in TVs, computers, smart phones, and tablets. Although the light emitted by most LEDs appears white, LEDs have peak emission in the blue light range (400–490 nm). The accumulating experimental evidence has indicated that exposure to blue light can affect many physiologic functions, and it can be used to treat circadian and sleep dysfunctions. However, blue light can also induce photoreceptor damage. Thus, it is important to consider the spectral output of LED-based light sources to minimize the danger that may be associated with blue light exposure. In this review, we summarize the current knowledge of the effects of blue light on the regulation of physiologic functions and the possible effects of blue light exposure on ocular health.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4734149/

Anecdotally: I look at a computer screen a lot,  well into the night, and noticed that I found it often hard to go to sleep. Looking into this, I learnt that computer screens and phones have a high colour temperature, strongly blue-biased, which led me to suspect it was messing with my day/night sense. i happened upon a program called f-lux  which allows you to alter the temperature and program it to alter with your 'day', such that the colour warms up as you enter evening. it seems to have done the trick and I don't get insomnia as often now. The colour of the light affects melatonin. I don't think it's voodoo.

Edited November 27, 2017 by StringJunky

[Endy0816]

Quote

The photopigment of photoreceptive ganglion cells, melanopsin, is excited by light mainly in the blue portion of the visible spectrum (absorption peaks at ~480 nanometers[6]).

https://en.m.wikipedia.org/wiki/Intrinsically_photosensitive_retinal_ganglion_cells

Yeah, both my phone and computer have a filter these days. Is odd seeing it shift though.

Edited November 27, 2017 by Endy0816

[Strange]

I wonder if the difference between the colour temperature of the screen and the ambient lighting is significant. I have also turned on the "night mode" (or whatever it is called) on laptop and phone. Not because I had noticed any problems sleeping but just because I found the increasingly blue light (as the ambient light got warmer) quite jarring by itself.

Your eye has to focus at different distances for different wavelengths so I wonder if that could be a cause of discomfort.

[DeoxyRiboRobert]

From what I'm aware blue light will obstruct melatonin production in your brain, preventing you from sleeping (Source). According to the study I linked people do result in having a low level of melatonin after exposure to large amounts of blue light as opposed to those without. If you miss out on sleep then you have an increased chance of suffering heart attacks or a number of different problems. I don't have the knowledge to contest the specific points you said about circadian rhythms

Therefore you could argue that large amounts of blue light could indirectly negatively impact health due to an absence of sleep?

 

[Alfred001]

Ok, so the sleep thing appears to indeed be legitimate. https://www.health.harvard.edu/staying-healthy/blue-light-has-a-dark-side

However, there are claims also made about it being bad for the eyes. Any science behind that?