I'll start this by stating that my left eye is near enough normal, but my right eye is quite short sighted. This means that I can get along fine without glasses, but I prefer to wear them (otherwise my eyes don't agree when trying to read, which is a strain).
This means that I first tried the Rift with glasses, and was a little annoyed at the Rift stealing them off my face every time I took it off. However I then tried without glasses, and my eyelashes immediately coated the centre of the Rift lenses with grease! This made the centre of the Rift view very blurry/smeared, as if I'd put a big fingerprint in the middle of my glasses.
For some reason my glasses don't have such a problem with my eyelashes, so from now on I wear my glasses with the Rift to protect the Rift lenses from my eyelashes, and maintain a clear view.
Who knew wearing glasses would be beneficial to VR!
flyingsaucers: I take it you don't wear glasses? in this instance I'd been for a shower about an hour prior, but being a stinky human being my skin secretes oils just like everyone else's. Lean your head against the car/bus/train window for a few minutes and take a look at the window afterwards, you'll probably see it's quite greasy from your head. It doesn't help that my eyelashes are annoyingly long.
ECBL: I'm certain. If you wear glasses you'll know exactly what it's like to have a smudge on your lens, and it was cleared up by cleaning the lens with the provided cloth. There is a huge difference between the "god rays" and having a patch of the centre of your vision blurred in one eye. I won't deny the god rays aren't an issue with the Rift, but they don't tend to affect the centre of view.
Optics like your smartphone glass usually have an oleophobic coating to help reduce fingerprints (yes that's those oils from your skin again), but there's a limit to how effective they can be.
