Hi! OP here. The screens are physically close, but the lenses give it an effective focal range of about 1.3m / 4'2", further than most monitors are placed. It feels a lot further, though.
As other posters have shared, the bigger issue is that the focal plane is static, at least until the varifocal technology matures. Getting good eye exercise outside of VR is important, just like it is with all-day computer work.
Is this really true? As someone who has never used VR, I assumed that an issue would be higher eye strain.