I had a friend who used a couple of different pairs, and they did help her for a few months, but then the prescription was no longer accurate.

As far as how bad is bad....BAD! I not only would have double, the images would appear far apart and usually one of them would be tilted. I would even have double vision with one eye covered at times, because the individual muscles were so weak that they eye couldn't balance itself. At my very worst, I had one iris pointing to the far corner of each eye and the eyes themselves kind of bulging out, because the muscles were so weak. Typically, tho, my right eye would drift toward my nose (cross-eyed) and sometimes go upward as well, almost being covered by my eyelid. I once took a photo of it, but it was so distressing and depressing that I deleted it.

When DV gets in the range of THAT bad, it really can do a number on your self esteem. Many people would assume I was "special needs" or "mentally challenged," especially when I'd speak with terribly slurred speech. If I had on sunglasses, they just assumed I was drunk! It was terrible and I hope I never return to that condition because I don't think I'll be so patient with others the next time.

Hope this helps.