There was discussion on another forum quite a few years back about the optical quality of eye pro effecting POA vs POI. IIRC it was for scoped rifle shooting.
The thesis was that cheap glasses altered and/or dispersed the path of the light travel enough that while your eye told you you were properly lined up in the eye box etc., you could actually be off center and misaligning the scope. I think the idea was that parallax issues would be worsened but it's been too long to remember the fine print.
So: does this sound like a legit concern?
If legit, does it have any effect with iron sights in general, particularly with pistol sights at pistol ranges?
How about interaction with RDS?