"The original version of this article stated that IR LEDs operate from 300-325THz (about 920-980nm), wavelengths that are invisible. Quite a few readers wrote to say that they could in fact just barely see the LEDs in some (or all) of their remotes. Several were kind enough to let me know which remotes these were, and I was able to test several on a spectrometer. Lo and behold, these remotes were using higher-frequency LEDs operating from 350-380THz (800-850nm), just overlapping the extreme edge of the visible range. "

Interesting. I had not read the footnotes. They should update the actual post rather than simply amending it in the footnotes.

Have you had cataract surgery? I know that can have an impact on visible spectrum depending on the replacement lens they put in.

Nope, I'm afraid not. I never noticed until maybe 3 years ago, so I think it's a newer development. I'm 31.

I also got glasses this year for the first time in my life, which the need for came on rather suddenly... So maybe it's linked with some kind of degeneration? I really can't say. I honestly didn't think to mention it to the doctor, but now I'm thinking maybe I should have.

I'm not an ophthalmologist, so if you are concerned about your eye health talk to one. That being said I was referencing that the human eye (retina) is capable of seeing a wider spectrum than we typically see. The natural lens filters out part of the spectrum (UV) that the synthetic replacement lenses do not filter out.

I expect this is because some actually produce light in the visible spectrum too.