OP - I've seen conflicting reports... I'm waiting on my Rift CV1 to arrive, and am wondering the same thing. I'm a bit long sighted now (see below) so I see clearly after about 5-6 feet. Dunno, I might need glasses in the Rift.
Main thing is to keep an eye (heh!) on eye strain - if you feel tired, rest and let your eyes relax.
If you can focus at normal monitor distance you don't need to wear glasses. Unfortunately I can't. I'm so short sighted I could probably use a headset that didn't use fresnels. Also, I'm getting on a bit which makes things worse so I had my optician make me some glasses with narrow band focus just for looking at a monitor. Luckily, these work really well with the Vive.
I feel your pain... I was horribly short-sighted (-11 left, -13 right with astigmatism in both eyes).
Luckily my lenses decided at 43 that they'd had enough, and cataracts set in - now I have 2 great new fixed-focus polycarbonate lenses, turned me intentionally mildly long-sighted, never seen better!