In response to a few points above: I have varifocals for my day to day specs. My riding glasses are just distance corrected as I can always take them off to look at a map or whatever. As I said, the view through the middle of the lens is A1, it’s just the glances up the trail lifting just my eyes rather than my head which are the problem.
I acknowledge that I only wear my contacts a couple of times a month, so maybe I’m just not used to making the choice between which eye to prioritise depending on my point of focus.
I use a local optician who have always been great and I’m sure will have useful advice, but as they don’t ride I wondered whether there was a magic, moon on a stick option that I ought to be aware of.