Blue light harmful - pseudoscience or legit?

[Alfred001]

I'm sure you've heard these claims as well, about the harmfulness of blue light emitted by computer/smartphone screens.

If I have it correctly, there are two sources of supposed harm:

1. disrupts circadian rhytm

Apparently, the blue light is of a color emitted by the sun, so if you use your computer/phone late at night, your body gets the impression the sun is out and this disrupts the circadian rhytm.

2. damage to some part of the eye

The other claim I think I recall hearing is that the light actually does damage to some part of the eye. This may seem highly dubious at first blush, since we're exposed to blue light from other sources a lot and if there's damage being done we'd be blind already, but it may be more nuanced than that. Sunlight is harmful to us even though we're exposed to it all the time and you wouldn't want to be overexposed to it.

So, is anyone familiar with what the scientific evidence says on this topic?

[exchemist]

5 minutes ago, Alfred001 said:

I'm sure you've heard these claims as well, about the harmfulness of blue light emitted by computer/smartphone screens.

If I have it correctly, there are two sources of supposed harm:

1. disrupts circadian rhytm

Apparently, the blue light is of a color emitted by the sun, so if you use your computer/phone late at night, your body gets the impression the sun is out and this disrupts the circadian rhytm.

2. damage to some part of the eye

The other claim I think I recall hearing is that the light actually does damage to some part of the eye. This may seem highly dubious at first blush, since we're exposed to blue light from other sources a lot and if there's damage being done we'd be blind already, but it may be more nuanced than that. Sunlight is harmful to us even though we're exposed to it all the time and you wouldn't want to be overexposed to it.

So, is anyone familiar with what the scientific evidence says on this topic?

Blue light from IT devices is said to be bad at bed time: . https://www.health.harvard.edu/staying-healthy/blue-light-has-a-dark-side. but I don't think anyone says it is generally harmful.

Some forms of blue light from LEDs contain a UV component. There are concerns that this can be harmful: https://journals.lww.com/health-physics/Fulltext/2020/05000/Light_Emitting_Diodes__LEDS___Implications_for.6.aspx

But I'm not sure whether definitive conclusions have been reached as to whether the risk in commercially available LEDs is significant or not. Maybe someone here will know.

 

[StringJunky]

Blue is higher energy and has a higher pathologically reactive potential than the other visible colours in that situation. 

Quote

How damaging is blue light for eyes?
Constant exposure to blue light over time could damage retinal cells and cause vision problems such as age-related macular degeneration. It can also contribute to cataracts, eye cancer and growths on the clear covering over the white part of the eye.3 Aug 2022

...

Constant exposure to blue light over time could damage retinal cells and cause vision problems such as age-related macular degeneration. It can also contribute to cataracts, eye cancer and growths on the clear covering over the white part of the eye. According to a vision study by the National Eye Institute, children are more at risk than adults because their eyes absorb more blue light from digital devices.

People also tend to blink less when using digital devices, which contributes to dry eye and eye strain. Other common signs of eye strain include headaches, blurred vision, and neck and shoulder pain. According to the Vision Council, 27% to 35% of Americans reported experiencing one of these symptoms after using digital devices.

https://health.ucdavis.edu/blog/cultivating-health/blue-light-effects-on-your-eyes-sleep-and-health/2022/08#:~:text=Constant exposure to blue light,white part of the eye.

 

[TheVat]

I switch my display to the amber setting, evenings.  Seems to do what it's supposed to - I have less eyestrain and go to sleep more easily.  (on those evenings I'm on a device; often opt for paper books instead, late in the evening) 

It's the kids I worry about a little.  Wife and I have two thousand volumes, roughly.  Ours kids each own around a dozen, and everything thing else they keep digitally.  On some level, I envy them, and might consider joining them.  Spouse, however, has a serious fetish for dead tree fibers and ink (and, to be fair, has books that are not digitally available and would cost a fortune to have all scanned).  And reading ink is so much easier on the eyes.  As someone pointed out in an article I read (in a paper magazine) long ago, print books have a slight three-dimensionality to the reading surface, combined with slight shifts of illumination, that is good for the eyes.  

[StringJunky]

If anybody tries the night light option, make sure you let your eyes adapt. Your eyes will adjust the colour of the light as near as it can to white, so you need to give it time to do that. Just before the point where the colourcast is obvious and too orange will give the maximum benefit, I think, without being annoying.