I have some issues, but fortunately I am long-sighted, so I'm not too bad riding except when reading a GPS or something. I too wear varifocals and, as has been said, the centre of the lens needs to be positioned correctly. Since, cycling, your head does tend to be dipped a little, the glasses are always wrong. I sometimes end up looking over the rims. I've broadly adapted though and never got around to looking for cycling-specific glasses. And yes, I'd need Dennis Taylor ones.