maybe you will find that reference in the topic interesting: https://community.openmr.ai/t/the-reason-why-fresnel-lenses-are-used-in-current-vr-hmd-generation/29904
Just understand first that the frensel lenses were specifically designed to minimise some dynamic distortions that we know can cause discomfort and motion sickness. The frensel lenses were not selected for low mass, low cost, hiding subpixel structure, filling SDE or any of the other crazy conspiracy theories I have read. They were the only practical lens technology for hitting the overall set of optimisations we wanted, especially minimising eye-position dependent distortion with a single element. They are not “cheap” lenses and need special equipment to make well. They are lower mass than the “equivalent” non-frensel profile lens, but that is mostly a happy coincidence, if a conventional lens could achieve the same performance in the axes we care about we’d happily tolerate the small mass increase for the reduced stray light and easier moulding. Our goal was to have lenses that worked well for everyone, from the least sensitive to the most easily nauseated. Some people just don’t perceive pupil swim, at least not until you tell them what to look for, and some people once they see it can’t unsee it and it ruins all HMDs with swimmy optics forever for them. Most concerning is that swimmy HMDs cause nausea at an almost subconscious level, you don’t need to perceive it for it to make your experience using the HMD unpleasant.
as far as I got it, it’s one of the ppl who worked in Valve on Index HMD
It’s for sure not about Pimax, their lenses make sick almost everybody if not positioned right, so I guess it’s better than non fresnel ones but still they did something wrong there.