I need weak distance glasses for driving (improves lettering on signs, but otherwise distance sight is pretty good) and much stronger reading glasses (as I've got older, my eyes can no longer accommodate to focus close up).
I was offered varifocals, but I found the geometric distortion, which varied as I turned my head, impossible to live with. Three different grades of lens were on offer; I went for the middle of the three. If an object passed my field of view while I was looking straight ahead, it would be tilted one way on the left of my vision, become vertical at the centre of my vision and then tilt the other way on the right of my vision. Rectangles and circles became parallelograms or ovals. The optician checked the centres of my eyes versus the lenses and found a slight error on one lens, so another set of glasses was made up, but they were just as bad. I certainly couldn't have driven in them. Even walking around made me dizzy. And I tried them for a couple of weeks to let my eyes get used to them.
The optician said that he'd never heard of anyone else reporting what I was seeing. He offered me the more expensive lenses but couldn't guarantee that the effect wouldn't be there, even if to a lesser extent. So I went for the back-up plan that they offered: two separate pairs of single-vision glasses (one for distance, one for reading) at the same price as the varifocals. Slightly inconvenient to have to carry around two pairs of glasses, but at least there's no geometric distortion.