Comment by Philpax

This is a real problem, but it's fine for most VR use cases as you're usually looking at content that's rendered at a distance greater than the focal plane. The problems start to occur when you look at nearby content - that is, content less than 2m away - as it ends up being extremely uncomfortable for your eyes.

There are solutions being developed for this, but they have not been successfully miniaturised and/or cost-reduced for productisation. It's unclear how far away it is at this time, but Reality Labs has several generations of solutions that physically change the distance between the lenses and the displays, and alternate solutions like lightfields capable of simultaneously displaying content at different focal planes are being investigated.