6 ms·
Questions: (a) Does this study sound plausible? (b) Would staring at the correct red color on a monitor work? Or would that not work since monitor colors are
by alister 6y ago
Questions:
(a) Does this study sound plausible?
(b) Would staring at the correct red color on a monitor work? Or would that not work since monitor colors are generated by mixing R, G, and B pixels and therefore not a pure wavelength?
(c) Would it be reasonable methodology to test one eye to see if it improves over the other eye?
- lsllc 6y agoI have one of those aviator LED flashlights that has the red LED for chart reading at night without destroying your night vision. I'm going to give this a try!
- briefcomment 6y agoPlease be careful, and stop as soon as you notice any discomfort.
- deleted 6y ago[deleted]
- eecc 6y agoMight be a good idea to stare at the light reflected from a white sheet of paper. The wavelength won’t change but the intensity (and FOV coverage ) certainly will
- GrayShade 6y agoHow about putting a diffuser (like a sheet of paper) in front of it?
- lsllc 6y agoOf course! The red LED is actually fairly dim, it's designed for pilots trying to read charts while flying at night! I got it for use with a telescope for looking operating a telescope without losing night vision.
- alister 6y agoAnother question: (d) How much does the precise wavelength matter? The study used 670nm but also mentions the range 650-1000nm. Lots of red-light gadgets are available on Amazon but how do you verify the wavelength? I was thinking of an optical spectrum analyzer[1] but at $28,000 they are shockingly expensive. Even with raw LEDs bought from a reliable electronics distributor like Digi-Key, it would be nice to be able to measure it somehow. [1] https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=5276 https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=52...
- cycomanic 6y agoI suspect you do not need to use 670nm exactly, however I suspect you need to be above 650nm. Note that many red LEDs are at a lower wavelength (~630nm). So you need to search for deep red or by wavelength. You can use a OSA, but yes they are expensive. Spectrometers are typically cheaper, but still expensive (you could go to a university optics group and ask them if they could measure it for you). That said if you buy from a reputable source you should get the right wavelength. If you are trying this out be careful with the brightness.
- joezydeco 6y agoInstead of trying to emit 670nm, why not just use a wide spectrum source and a 670nm bandpass filter?
- cleansingfire 6y agoLike the sun and your closed eyelids. Light transmission goes up with wavelength https://www.spiedigitallibrary.org/journals/journal-of-biomedical-optics/volume-16/issue-06/067011/Measuring-and-predicting-eyelid-spectral-transmittance/10.1117/1.3593151.full?SSO=1 https://www.spiedigitallibrary.org/journals/journal-of-biome... (see figure 5.) To speculate, perhaps we have evolved to benefit from closing our eyes in the sun.
- joezydeco 6y ago
- cycomanic 6y ago(a) not a medical person so can't answer this (b) unlikely, monitors work by essentially filtering out undesired colors from white light. I don't believe that >650nm light is within the color gammut of monitors. That's quite a long wavelength and close to infrared. To give you an indication, the Helium Neon lasers which used to be very common in schools etc for laser demonstrations have a wavelength of 632nm. Even if the monitor could display this, the brightness would likely not be strong enough. (c) Could be, but it might be quite annoying to do.
- Retric 6y agoThere are several different approaches to monitors, OLED RGB sub pixels individually emit light. https://en.wikipedia.org/wiki/OLED https://en.wikipedia.org/wiki/OLED. That said, your wider point stands.
- Markoff 6y agoC is the correct question to see, if this actually works
- lsiebert 6y agoThis is the hex value for 670 nanometre red. #ff0000 Per https://academo.org/demos/wavelength-to-colour-relationship/ https://academo.org/demos/wavelength-to-colour-relationship/
- Etheryte 6y agoThis only makes sense on a precisely calibrated display. On everything else, there's no way to tell what wavelength you actually end up with when you fill your screen with a color.
- contravariant 6y agoA perfectly calibrated display might still not be able to display pure wavelengths. At the very least if it's calibrated properly it won't normally do so at #ff0000 as pure 670nm is well outside the sRGB colour space.
- andy_ppp 6y agoI imagine the brightness of a monitor is not enough for there to be any effect but maybe I'm wrong?
- liziwizi 6y agoyes but when i drag the slider i see that 645-700nm is also ff0000. i don't know how precise it should be..
- rbanffy 6y agoI would assume one needs a very good laser+DLP projection system to make this work.
- emn13 6y agoAs to question (b): the wavelength is not the same. The red primaries in most color spaces, including wide-ish stuff like DCI-P3 is around 615. Even Rec 2020 is just 630. https://clarkvision.com/articles/color-spaces/ https://clarkvision.com/articles/color-spaces/ Note that it's fairly common to see chromaticity diagrams labelled with wavelengths around the edges, so you can check multiple sources if you want. I didn't read the original article in sufficient depth to tell you if the researchers even know what 615nm would do, but it's not 670nm anyhow ;-). Incidentally, the linked article also includes measured spectral responses for a few wide gamut screens, some of which have at least some response near 670nm. The most extreme on that page was the Del 3007WFP-HC LED, which peaked at 653, and has a wide peak hitting well over 700nm too (but below 650 too). A 2019 model Samsung Q80R qled TV (perhaps more common), had a peak at 632 nm, and at 670nm is about 20% as bright as at its peak.