> Many factors, like light scattering and imperfections in the eye’s optics, keep light from coming into sharp focus on the retina, Buabeng said.
> The study also found that iris pigmentation influenced how far apart the two light points needed to be before viewers could distinguish them as separate points. Using a standardized iris color chart, researchers classified each participant’s eye color before analyzing the results. Participants with lighter-colored irises, particularly blue eyes, experienced greater light scatter than those with darker brown irises.
Sounds like the research took a next step beyond previous studies on the same subject. You know, basically how science is supposed to work. Something anyone giving a flippant reply here could have figured out if they actually had read the article.
And did those studies use the same methods as this one? Because this makes it look like they didn't:
> Methods: In this retrospective cohort study, which is a subgroup analysis of a large prospective trial about visual impairments in European car drivers, we included 853 persons between 20 and 80 years of age and without a history of ocular surgery or any eye disease including cataract. Subjects participated in an ophthalmological examination, grading of lens opacity, and the measurement of visual functions such as IOSL, CS, and BCVA. Dependent on iris color, participants were divided into four groups: light-blue, blue-grey, green-hazel, and brown.
> The straylight function of the human eye depends on eye color, especially at larger angles of scattering. As a potential cause for this dependence, transmission of light through the ocular wall was measured, using a psychophysical method.
Even if this paper turns out to be the "boring" science kind that refines earlier results with different methods, it would still be science.
There have been estimates that up to 80% of published medical and psychology results arrive at incorrect conclusions due to methodological flaws, analysis flaws, and type I errors. And peer review's ability to weed out these problems is vastly overestimated by the public. 100% of the perhaps 80% of published papers that are incorrect made it past peer review.
So replicating and refining earlier results with different methods are really the best tool we have to ensure that science keeps progressing in a truthward direction.
I've had some light-sensitivity issues for as long as a remember. So I always get glasses with transitions. On computer though I've always been using flux [0] since it came out. I know that now a lot of OSes are supporting some kind of night mode, but I really like how there are some different parameters you can adjust in flux. And it's free.
I've discovered, for my part, that wearing yellow glasses works even better than f.lux when I'm working in an environment where I can't control the ambient lighting.
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On a related note, anyone wearing prescription glasses will be affected by chromatic aberration to some degree, which may notably cause the blue portion of the image to be shifted relative to the rest of the image, which makes text and other detail harder to see and can be annoying. This effect is accentuated when looking at a strongly trichromatic source like a computer or screen because the spectrum is discontinuous and the blue content has more power at shorter wavelengths than most natural sources.
You can mitigate this by using lenses made from a material with a higher Abbe value. Polycarbonate is the worst, CR-58 is the best, and Trivex is quite good. Trivex is also impact resistant, so it’s an excellent alternative to polycarbonate. The high-index plastics are quite bad, so if you don’t need them, consider asking for mid-index or Trivex instead.
I find it weird that in specific cases it's such a huge effect yet most of the time I can't notice it. Once when I got a new prescription I googled why the X in the red circle icon for closing a window is so off-centered, but it's just a case where chromatic aberration is really noticeable.
Eww, that's awful. Calcium fluorite has a rather low IOR and is very dense. What you want is a sapphire lens, except that the birefringence might be problematic.
I'm trying to get my hands on some decently high wattage (100W ideally) incandescent bulbs because it's really been bugging me lately that while I can still focus just fine, I have trouble making out details and some colours in artificial lighting. I've come to the conclusion that there's really no substitute for light generated from heat.
It hugely depends on the quality of the light. Look at CRI (and the newer, better TM-30). Low quality LED lighting is just terrible, the room appears light but colors and details are poor.
It's technically possible to achieve a 100 CRI score with a broad enough range of frequency spikes rather than the continuous range of frequencies you get from incandescent bulbs. So even the best LED bulb isn't going to match incandescent.
I have some LED bulbs at home but I use G9 halogens in either an E14 or an E27 adapter for the places where light quality is important to me. I tried a number of so-called "full spectrum" LED bulbs but I don't find the light they produce quite as satisfying as my halogens.
Philips Warm Glow A19 Medium Dimmable LED Light Bulb 479428, is something I've found. Phillips has been making more lights in the amber range. I really can't stand lights with higher kelvin ratings.
I really like the GE Sun Filled soft white bulbs (not the daylight version). They’re pricey and only 60w equivalent but they’re the closest to incandescent I’ve found.
From the paper's abstract (emphasis mine): "Wavelength influences multiple aspects of visual performance, yet its role in spatial resolution remains incompletely understood due to confounding factors such as luminance differences, chromatic aberration, and intraocular scatter."
They then did some modeling to estimate how well the results could be explained by scattering, chromatic aberration and, neural sampling (the cone cell density factor that you mentioned). They concluded that none of them could completely explain the observed results, but their results seemed to suggest the bulk of the effect is due to optical effects, with neurological factors as a secondary cause.
Refining existing knowledge by examining phenomena in more detail is how science should be done. The pressure to focus on discovering entirely new things is a major cause of the replication crisis.
Well, the title here at HN implies something else than the study shows.
If blue light actually impaired vision, that would be very notable. It would mean that removing the blue 'channel' for an RGB image would improve acuity. This is not what the study showed, however.
It is mainly just the basic fewer cones bit you mentioned. Which, btw, is easily experienced if you ever look from a distance at neon or led signs that only emit blue light. They'll persistently look out of focus when compared to their surroundings.
Yeah. I worked in the optical industry to pay for college. That was decades ago and one of the Drs I worked with and I had discussions on this. It was interesting at the time as I knew very little about optics when I started.
I certainly thought so. I have astigmatism and I cannot for the life of me read blue LED/neon signs at any reasonable distance at night. Any other colour, no problem. Blue is just a blurry mess.
I get that the guy needed to write a paper on something to get his PhD (in psychology, which might explain some of this as well, I thought standards were a little higher in the hard sciences), but don't know why it deserves a high profile. At least, based on merit.
In my neighborhood there is an optometry place with a dark blue lighted sign. At night, it looks fuzzy, and I have to assume they knew this would be the case. People walking by squint at it and inevitably think "maybe I _should_ get my eyes checked!"
Blue light also probably has more dispersion (aka chromatic aberration) .. I wonder how the eye deals with chromatic aberration, if we just filter it out by processing or if the system doesn't really suffer from it?
Edit: or perhaps that's the reason why we don't have high resolution in blue.
What’s your favourite illuminant? http://justine.lol/dox/illumination.txt It makes sense that black people might want to explore different ones than D65 if we consider the history of CIE colorimetry. Has anyone actually done a scientific inquiry into their ability to perceive radiation?
If you look at the spectrum of white LEDs they have a much higher blue light content than compared to other lighting technologies. Often it's an other peak in the spectrum.
Also a lot of street lights have been replaced with LEDs, although probably better than Sodium Vapor since that light source has pretty narrow spectrum.
Probably means we should all be using warmer LEDs, instead of like 5000K, 4000K ect... for night lighting.
Interesting, i've read in the past that blue lights are used sometimes in places where they want to dissuade people from intravenous drug use because the blue light makes it harder to find a vein. I wonder if that qualifies as fine detail.
The hospital toilets in Melbourne definitely have that setup. It was weird seeing basically every surface as just a shade of blue and nothing else.
I do wonder - now that most people have a phone with a flashlight - would not the druggies illuminate their own arms with white light and not be too bothered?
I've been noticing the affect of gold light during gold hour, specifically during sunset. I find I have more creative ideas for problems I've been chewing on come up, and also feel an indescribable calm. I've been trying to notice the affects of all the specific color phases of the sun and feel they each play a special role in our physiology.
I also wear glasses and I feel calmer and more "affected" during these periods when I take them off.
> The study also found that iris pigmentation influenced how far apart the two light points needed to be before viewers could distinguish them as separate points. Using a standardized iris color chart, researchers classified each participant’s eye color before analyzing the results. Participants with lighter-colored irises, particularly blue eyes, experienced greater light scatter than those with darker brown irises.
Sounds like the research took a next step beyond previous studies on the same subject. You know, basically how science is supposed to work. Something anyone giving a flippant reply here could have figured out if they actually had read the article.
https://pubmed.ncbi.nlm.nih.gov/22527312/
And 1991:
https://www.sciencedirect.com/science/article/abs/pii/004269...
It has to do with stray light diffusing much more easily through unpigmented irises than pigmented.
> Methods: In this retrospective cohort study, which is a subgroup analysis of a large prospective trial about visual impairments in European car drivers, we included 853 persons between 20 and 80 years of age and without a history of ocular surgery or any eye disease including cataract. Subjects participated in an ophthalmological examination, grading of lens opacity, and the measurement of visual functions such as IOSL, CS, and BCVA. Dependent on iris color, participants were divided into four groups: light-blue, blue-grey, green-hazel, and brown.
> The straylight function of the human eye depends on eye color, especially at larger angles of scattering. As a potential cause for this dependence, transmission of light through the ocular wall was measured, using a psychophysical method.
Even if this paper turns out to be the "boring" science kind that refines earlier results with different methods, it would still be science.
There have been estimates that up to 80% of published medical and psychology results arrive at incorrect conclusions due to methodological flaws, analysis flaws, and type I errors. And peer review's ability to weed out these problems is vastly overestimated by the public. 100% of the perhaps 80% of published papers that are incorrect made it past peer review.
So replicating and refining earlier results with different methods are really the best tool we have to ensure that science keeps progressing in a truthward direction.
[0] https://justgetflux.com/
You can mitigate this by using lenses made from a material with a higher Abbe value. Polycarbonate is the worst, CR-58 is the best, and Trivex is quite good. Trivex is also impact resistant, so it’s an excellent alternative to polycarbonate. The high-index plastics are quite bad, so if you don’t need them, consider asking for mid-index or Trivex instead.
Fluorite lenses FTW. Practically zero aberration. CR-58 pales in comparison.
Black body will probably always be better, but people unhappy with LED often have CRI < 80 LEDs when even 95+ isn’t necessarily great.
They then did some modeling to estimate how well the results could be explained by scattering, chromatic aberration and, neural sampling (the cone cell density factor that you mentioned). They concluded that none of them could completely explain the observed results, but their results seemed to suggest the bulk of the effect is due to optical effects, with neurological factors as a secondary cause.
Refining existing knowledge by examining phenomena in more detail is how science should be done. The pressure to focus on discovering entirely new things is a major cause of the replication crisis.
If blue light actually impaired vision, that would be very notable. It would mean that removing the blue 'channel' for an RGB image would improve acuity. This is not what the study showed, however.
It is mainly just the basic fewer cones bit you mentioned. Which, btw, is easily experienced if you ever look from a distance at neon or led signs that only emit blue light. They'll persistently look out of focus when compared to their surroundings.
It is extremely noticeable for me at night because I can never fully focus on signs using blue LEDs, while red LEDs give me no problem.
https://www.danielsternlighting.com/tech/bulbs/blue/bad/bad....
Also a lot of street lights have been replaced with LEDs, although probably better than Sodium Vapor since that light source has pretty narrow spectrum.
Probably means we should all be using warmer LEDs, instead of like 5000K, 4000K ect... for night lighting.
> Most flying insects cannot see red, orange or yellow light;
> Red preserves night vision. Blue keeps operators awake. Blue and white cause the worst glare. Jet instrument gauges are reddish/orange-ish.
See https://en.wikipedia.org/wiki/Metamerism_(color)
I do wonder - now that most people have a phone with a flashlight - would not the druggies illuminate their own arms with white light and not be too bothered?
I also wear glasses and I feel calmer and more "affected" during these periods when I take them off.