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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

#61

Post by bcoates »

pishpash wrote: post #11
goda90 wrote: post #6

Earlier quoted context omitted.

Well at least a start is to use software like f.lux that reduces the blue levels on the screen. There are also over screen filters and yellow tinted glasses that can filter the blue light.

It sounds like one should use it permanently, and not just at night. But the real problem is the spectral composition of the synthetic white light on screens. Now I want fluorescent backlights back.

Is there any reason to think that narrowband blue is worse than broadband blue? It makes for poor CRI when used as a light source but if the display blue is near the peak sensitivity frequency for blue it should result in slightly less total power being delivered to the eye than an equivalent blackbody spectrum white light.

Re: Chemists discover how blue light speeds blindness

#63

Post by rndmwlk »

_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…

That only happens for, what, less than a second before your eye adjusts? It's not like your eye knows it's day or night, and the pupil stays fixed.

Re: Chemists discover how blue light speeds blindness

#64

Post by rory096 »

shittyadmin wrote: post #30
kjullien wrote: post #8

Earlier quoted context omitted.

Use f.lux or an equivalent (most OS have their own implementation by now) that filters out the blue light at software/rendering level, it's not perfect but you do instantly feel the comfort it brings to your eyes. Been using f.lux for over 10 years and it also helps alot with going to sleep at night. When it's off your eyes/brain thinks that they are in daytime / broad daylight, when it's on I fall asleep 2 or 3 time…

The biggest problem I have with it is that everything looks so much worse that I just wind up turning it off all the time. Is this so seriously a threat to vision that it's worth it? I don't have the sleeping issues with screens some people seem to report, so I wasn't really willing to commit to it over that.

Make sure you change it to the "Slow: Natural Timing" transition speed so the shift is gradual. The faster speeds (which I believe are default) are jarring and too easy to notice.

Re: Chemists discover how blue light speeds blindness

#65

Post by xur17 »

asdkhadsj wrote: post #50
xur17 wrote: post #40

Earlier quoted context omitted.

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.

I'm using this [0] Home Assistant component. I also use a similar component to slowly turn my lights on in the morning instead of an alarm clock, which works really well.

[0] https://www.home-assistant.io/components/switch.flux/

Re: Chemists discover how blue light speeds blindness

#66

Post by Brakenshire »

rconti wrote: post #45
_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…

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 l…

Isn't blue light important in the mornings for keeping the circadian rhythm aligned? I thought you were supposed to avoid it in the evenings only. Probably it'd be fine for you if you're getting a lot of light, but might be bad if you don't.

Re: Chemists discover how blue light speeds blindness

#67

Post by derefr »

gregcrv wrote: post #34

"to wear sunglasses that can filter both UV and blue light" But isn't this bad with other consequences? I thought the lack of blue/violet light was the cause of myopia? https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5233810/

You can't develop myopia or hyperopia after your eyes/skull/orbital muscles are done growing. So this suggestion probably applies only to adults.

Keep in mind that this is age-related macular degeneration. Your photoreceptor cells are protected by the α-tocopherol until "a person's 50s or 60s." You wouldn't need any prophylactic interventions until then.

Re: Chemists discover how blue light speeds blindness

#68

Post by Brakenshire »

gumby wrote: post #38

Many of the comments here are about displays, but what about the LEDs sold as replacement for incandescent and halogen bulbs?

I think, white LED bulbs do use a single wavelength blue LED, but they pass it through phosphors which transform it into a similar distribution of wavelength that you would find from an incandescent bulb, or sunlight. LED's are a lot better than fluorescent lighting, which does often have very dramatic peaks and gaps.

In theory, you can look at the CRI rating, but in fact CRI only uses a small number of wavelength probes for the test, so a rating of 100 doesn't necessarily mean a smooth spectrum, it could be the manufacturer has tuned wavelength peaks in order to game the test. There are better rating systems being developed, but they're not used by manufacturers or mandated by governments yet.

I actually think it might be the lightbulbs that change colour which could be problematic. I wouldn't be suprised if some of those did generate the colour just with single wavelength blue, green and red sources. Hopefully the better ones would have individual phosphors for each r/g/b source which produces a spectrum which when combined is reasonable.

I would be particularly careful about cheap/unbranded colour-variable lightbulbs. I doubt they've been through much or any consumer testing, it seems you can buy anything straight off the boat from China through domestic web stores these days.

Re: Chemists discover how blue light speeds blindness

#69

Post by codemac »

Anyone have suggestions for kindles? A lot of the "screens" I've seen on amazon have pretty terrible reviews.

It's the one major source of nighttime blue light that I consume. I've largely given up using my phone / laptop in the dark, as I decided I'm an adult and can just leave the lights on.

Reading in bed is one of my favorite things, and it bothers my partner to leave the lights on.

Re: Chemists discover how blue light speeds blindness

#70

Post by JdeBP »

gambiting wrote: post #57
rconti wrote: post #46

Earlier quoted context omitted.

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.

I just don't understand how that could possibly work - it doesn't matter if the glasses absorb or reflect blue light - as long as it doesn't reach your eyes, anything that is normally white will look yellow, as you're not seeing the blue component. You can't filter/reflect blue light and still see it.

Colour perception is not that simple. The visual cortex compensates. It's the same sort of compensation that means that you see the same colours for objects under artificial lighting and in sunlight, even though spectral analysis will show them not to be.
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