[gre345t34]

This is inaccurate. Unlike IRL in which objects can appear at varying focal distances, requiring the eye muscles to constantly adjust the focal distance of the eye, the two images in a VR headset (one for each eye) remain at a constant focal distance as determined by the lenses.

The 3D illusion in VR comes from stereoscopy. The objects that appear in VR are actually all at the same focal distance.

[Kiro]

So why do you need glasses in VR? Just trying to understand.

[gre345t34]

Because there are lenses in the headset that focus the two images at a set focal distant (between a couple of meters and infinity focus, depending on the headset).

You need glasses for the same reason one would need glasses to see a flat image several meters aways, or to see the stars as the case may be.