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by emptybits·4y ago·view on hn ↗
"8 IR illuminators per eye"

Honest question: is there any reason to be concerned about such near and constant IR illumination directed at one's eyes?

6 comments
Generally with near-infrared emitters, the main issue is tissue heating up. Of course this depends on the tissue, the specific wavelength(s), and the angular distribution of the emitter.

OSRAM has an excellent datasheet about this, AN090 . If you're curious about how this kind of thing is safely engineered, have a look!

Also the reason for 8 emitters is to have lots of points to track, not to provide a huge amount of light.
“The most common eye disease associated with near-infrared radiation is cataracts. Prolonged exposure to IR radiation causes a gradual but irreversible opacity of the lens. Other forms of damage to the eye from IR exposure include scotoma, which is a loss of vision due to the damage to the retina. Even low-level IR absorption can cause symptoms such as redness of the eye, swelling, or hemorrhaging.”

https://ehs.lbl.gov/resource/documents/radiation-protection/...

It may even improve eye-sight in the short-term:

https://www.newscientist.com/article/2298723-red-light-thera...

I'm not sure about the energy and wavelength difference compared to the glasses. But even if it has a positive effect from short-term exposure, it may also have bad effect from too much exposure.

No, it's an insignificant increase over what your eyes already receive.
Does that account for the fact that it's decoupled from visible light? Afaik the iris contracts in response to visible light, so here could get exposed to more IR proportionally. (OTOH either way in absolute terms the amount you get from sunlight is orders of magnitude more than you'd get from a few LEDs.)
I guess it would be like looking up at one of those security cameras that are ringed with IR LEDs
Old tracking systems I tried were really uncomfortable due to that and couldn't be used long. Hope these are better (disclaimer it was 10 years ago).