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Chemists discover how blue light speeds blindness

phys.org

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Re: Chemists discover how blue light speeds blindness

#41

Post by rgrove »

_nkoa wrote: post #32
rgrove wrote: post #19

> To protect your eyes from blue light, Karunarathne advises to [...] avoid looking at your cell phones or tablets in the dark. Can someone explain why it would be worse to look at a cell phone in the dark? It's emitting the same blue light (or less, if the display gets dimmer) as it is in a bright environment. Why is that light more harmful in a dark environment?

Because of the way your eyes work. If it is bright, your pupil will be shrunk, to not be blinded by the luminosity. When it is dark, your pupil will be opened wide up. It is this principle that camera apertures are based on. Now if you have your pupil wide open in a completely dark environment and put a 100% brightness screen at ~10cm of your eyes, what do you expect will happen ? Our eyes are made for nature, that m…

Hmm. If I've been in the dark for a while and then pick up my phone, the brightness hurts my eyes for a moment until they adjust to it. When I put the phone down, it takes a moment before I begin to be able to see things in the dark room. Doesn't that indicate that my pupils were initially dilated in the darkness and then constricted when I began looking at my bright phone?

I wonder how significant the difference is between pupil dilation while looking at a bright phone in a dark room and while looking at a bright phone in a bright room.

Re: Chemists discover how blue light speeds blindness

#42

Post by degenerate »

friedman23 wrote: post #22

I use f.lux all day I don't know if I'm particularly sensitive or if it's all in my head but when I turn off f.lux, especially at night, to watch some movie or video I can physically feel my pupils dilate and it almost feels like my eyes go from being at rest to being strained.

Same - I have flux setup to be active during work hours (at work) and evening hours (at home) so it's filtering blue light on all my devices. When I accidentally close it or turn it off for a movie, I feel like a vampire in sunlight. I have such an easier time falling asleep thanks to flux.

Re: Chemists discover how blue light speeds blindness

#43

Post by rory096 »

Ntrails wrote: post #36
_nkoa wrote: post #32

Earlier quoted context omitted.

Because of the way your eyes work. If it is bright, your pupil will be shrunk, to not be blinded by the luminosity. When it is dark, your pupil will be opened wide up. It is this principle that camera apertures are based on. Now if you have your pupil wide open in a completely dark environment and put a 100% brightness screen at ~10cm of your eyes, what do you expect will happen ? Our eyes are made for nature, that m…

My phone (unlike my PC, or a TV) is smart, and thus dynamically alters brightness based on ambient light. It's pretty cool and certainly mitigaets the above somewhat

At least on my phone (LG G5), the lowest brightness setting is still incredibly bright in an otherwise dark room. I use Twilight[0] to dim it further, though unfortunately Google changed Android so it can't affect the soft buttons. (Which is fine for almost all apps because the soft button bar is black, but of course Chrome changes it to white with no way to fix it.)

[0] https://twilight.urbandroid.org

Re: Chemists discover how blue light speeds blindness

#44

Post by mafuyu »

I'm in the process of building a Philips Hue-compatible light therapy LED strip that goes above my bed, and I chose 500 nm cyan LEDs due to this concern. The goal is to have the lights gradually wake me up every morning and help align my sleep cycles, as I suffer from Delayed Phase Sleep Disorder.

Figure 3[0] in the paper seems to show that 500 nm is safe, and that melanopsin has high absorption at 500nm, which has important effects on circadian rhythm[1].

Anyone more knowledgable than me know if this setup is safe?

[0]: https://www.nature.com/articles/s41598-018-28254-8/figures/3 [1]: https://en.wikipedia.org/wiki/Melanopsin#Effects_on_circadia...

Re: Chemists discover how blue light speeds blindness

#45

Post by rconti »

_nkoa wrote: post #32
rgrove wrote: post #19

> To protect your eyes from blue light, Karunarathne advises to [...] avoid looking at your cell phones or tablets in the dark. Can someone explain why it would be worse to look at a cell phone in the dark? It's emitting the same blue light (or less, if the display gets dimmer) as it is in a bright environment. Why is that light more harmful in a dark environment?

Because of the way your eyes work. If it is bright, your pupil will be shrunk, to not be blinded by the luminosity. When it is dark, your pupil will be opened wide up. It is this principle that camera apertures are based on. Now if you have your pupil wide open in a completely dark environment and put a 100% brightness screen at ~10cm of your eyes, what do you expect will happen ? Our eyes are made for nature, that m…

Interesting; when I got 2 new pair of eyeglasses last month, again I fell for the usual "buy all the coatings" spiel. I didn't much understand what they were, but I was told one causes refractions that bother some people.

I absolutely notice a blue refraction from car headlights when driving at night. I keep thinking I'm seeing a police light from somewhere. It's fine, just interesting. Well, after looking at a few lens coating websites, and realizing my lenses reflect blue light back at me if I have a light source to reflect, they're obviously blocking blue light -- cool!

I've never been much for f.lux style color shifting, I HATE the obviously inaccurate colors. I also wonder if we'll find that some of these technologies don't work nearly as well as a blue filter, and that perhaps the light just LOOKS less blue.

But I'm sure glad to have glasses that now block some blue light. Also, it validates my desire to keep the blinds open at work; I have LOTS of light coming into my cubicle area. Sometimes it's even a bit annoying but keeping my pupils small should help.

Re: Chemists discover how blue light speeds blindness

#46

Post by rconti »

gambiting wrote: post #27
burkemw3 wrote: post #20

Earlier quoted context omitted.

You can wear glasses that filter blue light. The article mentions wearing them outside, but they work inside as well. I wear them, and they provide other benefits for me as well ( https://news.ycombinator.com/item?id=16529054#16531413 )

So I used to have glasses with a blue blocker filter on them - I absolutely hated every second of wearing them. Literally everything appeared yellow through them - my screens, sheets of paper, even snow looked like it had been peed on - awful. I mean, it's certainly not surprising - they did block blue light after all. But I wore them for 3 months and then marched back to the optician to have them replaced with norma…

My new eyeglasses have a coating that reflect blue light. They absolutely do NOT shift the color spectrum. You can't tell the coating is there. Perhaps it's newer or different tech. Look into it.

Re: Chemists discover how blue light speeds blindness

#47

Post by lawlessone »

corpMaverick wrote: post #15

From the article... To protect your eyes from blue light, Karunarathne advises to wear sunglasses that can filter both UV and blue light outside and avoid looking at your cell phones or tablets in the dark." Please share any additional actionable advice.

Wear Sunscreen

Start a pension.

Re: Chemists discover how blue light speeds blindness

#48

Post by danaos »

friedman23 wrote: post #22

I use f.lux all day I don't know if I'm particularly sensitive or if it's all in my head but when I turn off f.lux, especially at night, to watch some movie or video I can physically feel my pupils dilate and it almost feels like my eyes go from being at rest to being strained.

As a linux user, I have found that Redshift works better than f.lux. It's the first thing that I install on a new machine of mine.

Re: Chemists discover how blue light speeds blindness

#49

Post by asdkhadsj »

rgrove wrote: post #41
_nkoa wrote: post #32

Earlier quoted context omitted.

Because of the way your eyes work. If it is bright, your pupil will be shrunk, to not be blinded by the luminosity. When it is dark, your pupil will be opened wide up. It is this principle that camera apertures are based on. Now if you have your pupil wide open in a completely dark environment and put a 100% brightness screen at ~10cm of your eyes, what do you expect will happen ? Our eyes are made for nature, that m…

Hmm. If I've been in the dark for a while and then pick up my phone, the brightness hurts my eyes for a moment until they adjust to it. When I put the phone down, it takes a moment before I begin to be able to see things in the dark room. Doesn't that indicate that my pupils were initially dilated in the darkness and then constricted when I began looking at my bright phone? I wonder how significant the difference is…

If it is the delay in dilation that causes the damage, I imagine it's exacerbated by constantly changing dilation as well. Ie, if I'm staring at my phone in the dark, I rarely keep focus on it. I often glance to the left or w/e, thus causing the screen to appear too bright again. Same for laptop-ing in the dark. I often find myself looking at keys, or thinking off in the distance, or w/e.

Re: Chemists discover how blue light speeds blindness

#50

Post by asdkhadsj »

xur17 wrote: post #40
friedman23 wrote: post #22

I use f.lux all day I don't know if I'm particularly sensitive or if it's all in my head but when I turn off f.lux, especially at night, to watch some movie or video I can physically feel my pupils dilate and it almost feels like my eyes go from being at rest to being strained.

I use something similar to flux for my lightbulbs, and I've noticed the same thing when I disable it at night. My eyes are definitely strained.

Care to link what you're using? It would be nice to modify my room to use changing color spectrum bulbs depending on the time of day.
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