Truth no fixed optics headsets that use soft ipd adjustment.
The lenses themselves are not the issue but using average ipd for physical space between lens centers will cause annoyances/strain with those who's ipd are considerably outside of this value regardless if it's plus or minus.
So PiMax 4k/BE, PSVR, GearVR, Deepoon E3 etc
With GearVR/Rift there is a gentleman selling 3d printed ipd lens adapters. It would be good to contact him about making them for pimax headsets as well.