I helped a family member set up a 16e today and decided I may as well measure the flicker level while I'm at it. I already had a migraine so I can't speak to the effects of the display on my eyes, but it didn't feel horrible from the few minutes I used it.
The strongest flicker is the refresh rate at 60 Hz, then the PWM rate seems to be 480 Hz no matter the brightness setting, but the amount of flicker changes.
At 0% there is effectively 100% flicker.
At 10% there is about 20-50% flicker. (20% when measured at high amplification, 50% when measured at low amplification. I need to redo this test to make sure which is more accurate).
At 25% there is about 20% flicker.
At 50% there is about 20% flicker.
At 75% there is about 20% flicker.
At 100% there is about 20% flicker.
And of course I can't just state a bunch of facts without providing evidence. Screenshots from the oscilloscope below. Equipment used: Siglent SDS1000X-E oscilloscope and Thorlabs PDA100A2 amplified detector.
0% brightness
10% brightness
25% brightness
50% brightness
75% brightness
100% brightness
You'll notice that the frequency displayed on screen is a bit inaccurate because it's difficult to trigger properly with this type of signal, but counting the peaks per division puts it at close to 500 Hz, which is in agreement with the 480 Hz measurement I got at 10% brightness, which I did confirm with multiple measurements at different brightness levels.