Comment by teslabox

The shift to unsafe high-blue lights is simply a matter of forgetting what was figured out. In the 20th century the lighting companies (GE, etc) had all the money in the world, and spent a lot on R&D. They figured out how to get the most efficient lights possible for their customers. The scientists figured out exactly how blue light causes inflammation in our eyes. There are good reasons why cities used orange High Pressure Sodium [HPS] Bulbs for street lights: HPS is very energy efficient (as good as most LEDs), and they emit light that is almost blue-free.

Then LEDs were invented by companies that didn't have that old R&D. The automotive industry gradually switched to LEDs for the advantage of not needing to replace bulbs (but lights that fail are now >$1000 to replace instead of $5)

Instead of putting safe low-blue LEDs on their cars (~2400K), auto manufacturers are using 4000K to 5000K LEDs. These have too much blue light.

To understand modern lighting, the term "spectral power distribution" is quite helpful: https://news.ycombinator.com/item?id=27334405

In 2020 I sat down to think about why blue light at night is so terrible, and sort of figured it out.