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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

#121
post #45
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…

> perhaps the light just LOOKS less blue.

That is a really interesting distinction! Blue is a color derived by social consensus, but it is also a particular wavelength of photons. I'm curious about what's there if we dive in and examine what specific wavelengths of light (numerically) cause damage, and what is the overlap with what we typically consider the color blue. I'm sure it's not one to one.

Re: Chemists discover how blue light speeds blindness

#122
Lots of comments here about blue-less lighting at night, so I thought I'd share my experiences in trying to warm-ify our household lighting. I'm in no way an expert; just sharing some experience.

It all started when we moved in to our current place. The previous tenants had left a bunch of old incandescent bulbs. I guess I had forgotten in the past two decades just how warm colored those lights are. It is a really comforting color temperature and great for getting sleepy before bedtime. Of course when I went to replace them with LEDs the contrast was obvious.

Now enlightened (heh) to the differences I went on a quest for warm colored LEDs. Turns out, that's really difficult. First I bought just any old light with the word "warm". But most LEDs you find are actually "warm white" or "soft white". Basically 2700K and up. Whereas old school incan. is ~2400K. The difference is huge and I was very disappointed.

So I began to filter my searches looking for things in the 2400K range. The local lighting store had _nothing_ (a store completely dedicated to selling lights). Amazon had a few options, but not many. Once you filter by low temperature and dimmable you begin to scrape the bottom of the barrel. Most were off-brand, which I try to avoid since poor quality LEDs will fail early when their cheap power supplies burn out.

I went through a few rounds of orders but finally settled on a set of Philips dimmable A15 lights "with warm glow effect". They are small enough to fit in all fixtures I've run into for those kinds of bulbs. But the best feature is that they change temperature as you dim them. So you have the option of a cooler "soft white" (2700K) at full brightness, or all the way down to 2200K when dimmed! To a non-expert in lighting they subjectively looked the best and gave us the same warm, comforting glow we were looking for at night.

So my advice, if you're looking to upgrade your house to warm bulbs, make sure to look for something 2400K or less.

Others have mentioned checking CRI, and that's important. I don't know the CRI on the bulbs I got. Again, they subjectively looked the best. But there aren't a lot of options in the truly warm color range so it's a feature I had to not care much about.

I also found some really great vintage filament style LED bulbs for a project (vintage style outdoor string lights with corded wiring; built from scratch). They're from a company I found on Amazon called Cmyk. Off brand, but they're the best option I found in that category and their packaging was actually really professional. They are labelled as 2200K, but they look even warmer than that. When dimmed about half way you get just the right amount of glow that you can see the faux-filaments. Super happy with those.

Beyond that you can also just get color-changing bulbs like Philips Hue. Since all this went down I've been slowly upgrading to those instead. That gives you the option to choose really any temperature you want at any point. I'm not sure how the "quality" of light from that setup compares to a real warm LED lightbulb. Obviously you're getting a "warm" color by mixing red and green LEDs so it isn't a true color temperature. But on the other hand you're definitely not getting blue light, which is the important thing. Either way, subjectively they look great and I wouldn't be able to tell the difference. (Usual caveats about buying into a somewhat closed system applies; Philips Hues are sort of the best worst option today.)

Re: Chemists discover how blue light speeds blindness

#123
post #110
post #83

Earlier quoted context omitted.

I'm sorry I can't help you, but after reading an article posted here about melatonin I got interested in light therapy, but commercial devices are a bit expensive. Are you documenting your project?

Sure, it's not the most exciting project, but I might do a short writeup when I'm done. I originally purchased these nice LED strip bars with enclosure in blue[0], but after reading this site by the manufacturers of a commercial green therapy light[1], I was convinced to switch to turquoise/cyan. Turquoise isn't that popular so I wasn't able to find any strips/bars, and I got these individual 3W bead LED modules inst…

You're a hero; thank you for posting details.

Re: Chemists discover how blue light speeds blindness

#124
post #55

Earlier quoted context omitted.

iOS is the same. Even on the warmest setting and lowest brightness it's still very bright. Unfortunately, there is no app to do anything about it like there is on Android.

You can configure iOS Home button triple-click to invert the screen, so it's white text on a black background. There is a "Smart Invert" option so that photos are not affected.

I'm on X so no more Home button, but good suggestion. For last 9 months I had my phone on grayscale, which was nice, but still a bit high for my taste.

Re: Chemists discover how blue light speeds blindness

#125
post #44

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 i…

Wow that's totally what I have too. I didn't think there was a name for it.

I mean the delayed phase sleep disorder. Will talk to the doc about it.

Re: Chemists discover how blue light speeds blindness

#126

For the f.lux Mac users here, do you prefer that to Mac's Night Shift? I just found this article, which details why f.lux is better than Night Shift. But it's written by f.lux, so it's a bit biased. https://9to5mac.com/2017/03/28/flux-developer-says-apples-ne... I'm guessing both are better than nothing, but is one actually better than the other?

I've been using F.lux for over seven years. Advantages… - You have a great deal of control over the blue level. Night Shift's blue level is higher than F.lux's default, and not adjustable. - Flux transitions more naturally as the sun goes down. - More scheduling options, "disable until tomorrow". - the big one: disabling per-app or for full-screen apps. You probably don't want Flux on while watching a movie or bingin…

First point is incorrect. Night Shift's color temperature is adjustable, which includes the blue level.

Re: Chemists discover how blue light speeds blindness

#127
post #44

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 i…

I work with reef aquariums and we use something similar for our reef tanks at the store to wake up the corals

Re: Chemists discover how blue light speeds blindness

#128
post #72
post #55

Earlier quoted context omitted.

iOS is the same. Even on the warmest setting and lowest brightness it's still very bright. Unfortunately, there is no app to do anything about it like there is on Android.

You can go further by reducing white point in accessibility settings. The colour filters there also go beyond night shift.

Interesting. I was on grayscale for last couple of months, but didn't know I can reduce the white point also. Will try.

Re: Chemists discover how blue light speeds blindness

#129

Here’s the actual study, thanks to sci-hub: http://twin.sci-hub.tw/6979/4112e16f7195f7f33cd3e861c6345df0...

The post's URL actually includes links to the sci rep paper and the full text pdf paper is available from there for free for everyone. No sci-hub needed.

http://www.nature.com/articles/s41598-018-28254-8

http://www.nature.com/articles/s41598-018-28254-8.pdf

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