Declining eyesight improved by looking at deep red light

Re:Declining eyesight improved by looking at deep red light by cycomanic on Tuesday June 30, 2020 @02:45AM (#23687325)

I 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.

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Re:Declining eyesight improved by looking at deep red light by joezydeco on Tuesday June 30, 2020 @10:12AM (#23690164)

Instead of trying to emit 670nm, why not just use a wide spectrum source and a 670nm bandpass filter?

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Re:Declining eyesight improved by looking at deep red light by cleansingfire on Tuesday June 30, 2020 @07:44PM (#23696143)

Like the sun and your closed eyelids. Light transmission goes up with wavelength 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.

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Re:Declining eyesight improved by looking at deep red light by joezydeco on Wednesday July 01, 2020 @01:32PM (#23704127)

That's a great connection. If it's that simple (and explained by human evolution), that would be awesome.

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