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In short, I have some sort of vision problem that seems frustratingly hard to diagnose. I am night blind in my peripheral, overly sensitive to blue, and sources of light have a starburst pattern instead of the actual shape.

My question: Is it possible to filter out UV, Purple, and Blue light (most of the upper spectrum of light) without darkening the remainder? Also is there a way to bend IR into the red colour range so that it can be seen? How would a person make or assemble this as a non-powered device and what would be required?

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UV, Purple, and Blue light (most of the upper spectrum of light) without darkening the remainder?

Yes, you can buy longpass filters at pretty much any wavelength range you want. Technically it's impossible for them not to darken the remainder at all, but they should transmit 99% so not noticeably darkened.

Cheaper and easier is just a pair of yellow tinted sunglasses.

is there a way to bend IR into the red colour range so that it can be seen

Not really. Infrared radiation is lower energy then red, so you would need a way of giving the light more energy, which is tricky without using power!

There are special materials which allow 2 infrared photons to be combined into a visible photon with twice the energy, but the efficiency is so low that it is only really practical with a laser beam where you have a LOT of photons.

Another technique is to use high energy (blue or UV) photons to excite some special chemicals so that a low energy infrared photon arrives and triggers it to give off visible light. The extra energy comes from the blue or UV exciting photon. But this requires that no other photons arrive to trigger the material and so only works in the dark and with strong infrared sources.

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  • $\begingroup$ excellent answer. I have in fact already tried yellow shooter's glasses, they offer some help but I was hoping to fabricate something stronger. I will research these "long pass" filters. Would it be possible to make a long pass filter out of something nontoxic and malleable, with the intent to install it in the iris? $\endgroup$ – Andro Id Aug 23 '16 at 22:48
  • $\begingroup$ A thin film of gold works very well to block blue. Gold plated contact lenses? $\endgroup$ – Martin Beckett Aug 24 '16 at 4:29
  • $\begingroup$ Sweet answer, I happen to already deal with plating companies. Any idea which colour of gold ? Satin rose etc? How thick? 1mm or like micrometers or like 150 nanometers? $\endgroup$ – Andro Id Aug 25 '16 at 22:50
  • $\begingroup$ @AndroId probably 20-50nm. It's easy to calculate the transmission of thin gold film analytically. The coating companies have software that will design the coating. $\endgroup$ – Martin Beckett Aug 26 '16 at 4:23

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