Some data and what they tell usRiftS and IPD
A few days ago i created a simple poll asking people for their IPD and if they had problems using the headset, let’s take a look at the results.While it can be assumed that the survey would be biased towards negative outcome, as people who have issues are more likely to respond. What I didn’t assume is that there would be people submitting the form many times with negative answer to prove that Rift S is not comfort-able.

So the only thing this survey definitively proves that there are people biased against Rift S.
Some actual data?
After deleting the answers from above, here is the graph on how it turned out.
As a final note, let’s just say that eye-strain is caused by multiple factors and things like headset refresh-rate, the asymmetry of your eyes, panel type, low-persistence and couple of other factors also play a role. Rift S dropped refresh rate from 90Hz to 80Hz, which alone may be causing problems for some people.
P.S.: Notice that a lot more people report even IPD than odd.