Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Chemists discover how blue light speeds blindness

phys.org

Post reply on HN
Print view View original

101–110 of 345 posts

Re: Chemists discover how blue light speeds blindness

#101

Post by vosper »

astrodust wrote: post #88
JimboOmega wrote: post #81

I don't quite understand. Blue light - any blue light - causes blindness? So we shouldn't look at the sky even? I've never heard blue being a danger other than its effect on the biological clock, so that seems like a pretty bold claim. Ultraviolet, sure... Though buried in there is something about immune system and vitamin E levels... I really find it hard to believe that blue light exposure is automatically bad. We…

We have chemical receptors on our tongue and in our nose for poisons. We have neurons that detect pain. Just because we can sense it doesn't mean it's not harmful.

But those receptors signal something unpleasant - a terrible taste, pain. Looking at blue doesn't cause pain or unpleasantness.

Re: Chemists discover how blue light speeds blindness

#102

Post by rconti »

JdeBP wrote: post #70
gambiting wrote: post #57

Earlier quoted context omitted.

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.

Yup. I don't know how else to explain it. Trust me, I'm very sensitive to color temperature changes. I have 4 pair of eyeglasses I rotate through every day. Only 2 of them have the latest anti-blue coating. You simply cannot see it. I don't know what product it is, but a good example description from Zeiss:

https://www.zeiss.com/vision-care/en_us/products/coating-col...

Re: Chemists discover how blue light speeds blindness

#103

Post by btrettel »

kypro wrote: post #7
kjullien wrote: post #3

Did we not already know about this ? I remember 5+ years ago blue LEDs were pulled off of the market (at least in France) because the spectrum they emit in is way too close to uv and could burn your macula.

Wait, is UV light bad for your eyes? Should I be careful about visiting bars with UV light too?

When I did research as an undergraduate, one of the MS students in the lab I was working in moved a powerful UV light used to cure glues from the corner of the room to the center and used it without putting a box over it as was standard procedure. Of course, he didn't look at the light himself, but he also didn't announce its use either. I saw the UV light as I was walking through the lab. It was basically a bright purple/blue light. Several hours later I was effectively blind due to pain, which continued for a few days. I basically had the equivalent of a bad sunburn on my eyes.

This was one of several reasons I quit that lab. Since then I've avoided academic labs that have UV lights or lasers because I don't trust that the students follow safety procedures at all.

Re: Chemists discover how blue light speeds blindness

#104

Post by programUrJerb »

>Karunarathne introduced retinal molecules to other cell types in the body, such as cancer cells, heart cells and neurons. When exposed to blue light, these cell types died as a result of the combination with retinal. Blue light alone or retinal without blue light had no effect on cells.

Does anyone disagree that this is equivalent to looking at a phone?

Re: Chemists discover how blue light speeds blindness

#105

Post by stephengillie »

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

My TV, a Toshiba Regza, has dynamic brightness. It works very well as my primary monitor.

Re: Chemists discover how blue light speeds blindness

#106

Post by hestipod »

walterbell wrote: post #95
hestipod wrote: post #87

This or something connected to it is literally ruining my last chance at life but I cannot solve it and there is always a catch. I was disabled long ago by bad surgery and left in lots of pain. My physical career was ended. I was denied social assistance and fell in every crack. Life has never been stable enough long enough to reeducate and rebuild. In suicidal desperation I posted in a few places asking for ideas. A…

Do you wear glasses? Have you tried an iPad Pro with 120Hz refresh + Night Shift? How much ambient light do you have when using the computer? Is the ambient light natural or artificial? If artificial, what spectrum/type?

Sorry I updated the post as I knew I would leave some things out as I am a mental wreck and this is long and complicated. I don't wear glasses. I have monovision from Lasik done 20 years ago and am starting to have presbyopia in the distance eye but it doesn't cause issues with CCFL displays or reading or anything else. I just have aapprox 3" window 10-12" from my face where neither eye is focusing well but displays are twice that far away and the doctor said it shouldn't matter or need correction. I have tried OTC readers with the close eye lens removed to try and close the gap and it doesn't seem to change this problem.

Refresh rates and software filters don't seem to matter so far. I have this strain by a well lit window with great natural light (sometimes oddly enough direct natural light can sort of "overpower" the sharpness of the display and make it look more like E-ink and it SEEMS less bad then but hard to tell once it begins. At night I have 4x 60w incandescents in my room with no real change overall. In stores with intense LED or tube lighting it happens just as fast.

Re: Chemists discover how blue light speeds blindness

#107

Post by upofadown »

It is already known that you can damage retinal tissue with the light from blue LEDs. At a particular power density blue will be the more damaging colour as it has the highest energy. So the question is if the intensities and duration of exposure encountered in day to day life can cause permanent damage to the retina.

Re: Chemists discover how blue light speeds blindness

#109

Post by niceperson »

_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…

Would using a kindle at night have the same effect? It's light is kind of yellowish (I think)

Re: Chemists discover how blue light speeds blindness

#110

Post by mafuyu »

priccis wrote: post #83
mafuyu wrote: 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'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 instead.[2]

For the Hue integration, I'm using a Mesh Bee + UartSBee v5[3] with firmware from PeeVeeOne[4]. It outputs PWM, and I'm hooking it up to a cheapo constant current LED driver I got from Aliexpress. Since all the LEDs need to be in series for a constant current driver, I'm probably looking at a ~20V power supply to power the whole thing.

My bedframe has a headboard, so I'm planning on 3D printing some mounts that clamp on top.

[0]: https://www.ebay.com/itm/50CM-U-Aluminium-shell-DC-12V-36-SM...

[1]: http://www.sunnexbiotech.com/blue%20vs%20green%20light.html

[2]: https://www.aliexpress.com/item/10-pcs-3W-Turquoise-Cyan-LED...

[3a]: https://www.seeedstudio.com/Mesh-Bee-Open-Source-Zigbee-Pro-...

[3b]: https://www.seeedstudio.com/UartSBee-V5-p-1752.html

[4]: https://peeveeone.com/?page_id=252

Post reply on HN