Thanks! Thought it might be some ocular/VR term I hadn’t heard before. In game FPS, I’m familiar with.
It's the same FPS, it's just on the headset screens instead of the monitor screen. When the CV1 Rift was developed the designers believed from testing that 90 FPS was the minimum for comfortable VR. Later they were able to improve the timing between frames so that a lower FPS was usable. Then they developed the Quest with 70 FPS max and the Rift S at 80 FPS. Point being that FPS is a bigger deal with VR than with a monitor where 60 FPS is normal but even with a monitor there are noticeable advantages to higher frame rates.
I always recommend adjusting visual quality for the max FPS your VR headset can manage, or at least 90 FPS if it can go higher.
Also, my VR headset looked a lot better after my cataracts were removed, so checking any vision issues with your eye doctor is a good idea.
Monitors look sharper than VR headsets because while both use tiny pixels to create images, the monitor is usually a few feet away from you so the pixels aren't noticeable while the VR headset uses Fresnel lenses that magnify the pixels to make the tiny screens look bigger than your monitor screen.