Interestingly enough, the focal length of the lenses and perceived distance due to stereoscopic parallax are completely unrelated.

The lenses can't reshape themselves, so the screens have to always sit at a constant perceived distance from your eyes, typically set around the middle of where the eyes are used to focusing, about 2 meters away. This isn't a problem, because the effect of the brain taking depth cues from parallax is much stronger, so the focal length detail just fades into the background.

What this all means though is that whether or not you need glasses in a VR headset is entirely dependent on whether you need glasses to see objects 2 meters away outside VR. This remains true even when objects in VR are much closer or farther as perceived by stereoscopic vision.

Out of curiosity, what FPV goggles are you using? (Edit: nvm, I saw the name in a different comment)

I've been running the HDzero Box Pros and they are pretty comfortable in terms of closeness to screen. Definitely different than VR- feels more like sitting in a movie theater rather than looking through binoculars. Not as pixelated as early VR or FPV either.

I wish the Index had a fan like the box pros, it helps a lot.

Do you have stereoscopic goggles or box goggles? Boxes make my eyes hurt after a while. The ones with lenses still put the screen pretty close but it's a lot easier on the eyes. As a bonus, you can adjust the focus of each so you can correct for vision without mashing your glasses in there.