A beam of non-visible radiation can cause secondary radiation in various ways. Hopefully it’s the dust in the air fluorescing or being heated. Black-body radiation from some part of your eye would be concerning.

Additionally human eyes are sensitive to near infrared. Go look at a TV remote in a really dark place. Check with your phone because your phone can see it. If you can't then check with the nearest child, they'll tell you.

You lose sensitivity to this bandwidth as you get older. But if it's bright enough you'll see it. It's not like there's a hard cutoff in your eyes detection, it decays and you're very insensitive to big bandwidth, but not necessarily blind to them

Now that you mention it, I do remember occasionally being able to pick up on a faint red light in the remote control back when I was younger. It was easier to see with a phone’s camera I think?

Yes, your phone will be able to pick up many of these lights. Though some controllers no longer use IR technology so if you don't see it this could be an explanation. If in doubt, check with a child lol.

This may be due to changes in the sources used for remotes over time perhaps.

> There was a slight loss of -0.6 dB per decade in the cumulative threshold, but regression analysis showed the lack of a significant correlation between age and sensitivity. The intergroup analysis confirmed that infrared vision did not significantly differ between the four decades of life. The sensitivity level did not significantly correlate with visual acuity, spherical equivalent, retinal thickness or straylight parameter. The comparison of values measured at the seven locations showed a significant difference between the central (19.7 ±2.2dB) and the peripheral retina (22.5 ±2.4dB).

Source: https://iovs.arvojournals.org/article.aspx?articleid=2745068