I've been using prescription lenses with my HTC Vive for a year now and they're fantastic. Wearing glasses is really inconvenient because adjusting the position of them can require taking the headset off, and they usually overlap badly with the headset lenses (so there are parts at the side I don't see and parts above and below that I don't need to see). With lenses on my headset all I have to do is put the headset on and I have normal corrected vision of virtual reality with no loss of view.
I purchased them from VR Optician (previously VR-Lens.eu
) and would strongly recommend them for anyone using VR who wears glasses. They fit on top of the Vive display and are easily removable.