Origin of the question
I have recently finished an internship at a (small) game development company which is working on a Virtual Reality game that is also used in medical rehabilitation. From what I have heard and read online, you generally want to achieve at least 90 FPS in a VR game because otherwise the player can get motion sickness or dizzyness, etc.
I am aware that not everyone is getting sick but from what I have read, you still want to aim for that 90 FPS to be sure, although I am unable to find the exact reason for this number. (it feels like an industry standard)
"Why is 90 FPS an industry standard when developing a VR game?" and "Why can people get sick when playing on lower frame rates?"
When searching online, I keep reading about 'studies' that show that people will be more likely to feel sick or dizzy when playing a VR game below 90 FPS but I never see the actual reason (source) as to why that is.
I can only make assumptions based on what I know already but I would like to know the exact reason (or as much of a reason as possible) and hopefully a source as to why 90 FPS is chosen (and not 80 or 100) and what causes some people to become sick from lower framerates.
sidenote: I am referring to VR games for devices as the 'Vive', 'Rift', etc. (as there are also VR Simulations for pilots, etc. which also have elements such as simulated movement that can impact sickness)