20/20 correction
20/20 correction is a correction you normally get from a licensed optician, which corrects your eyesight up to a degree of visual acuity that an emmetropic (or "normal-seeing") person achieves on a Snellen Chart.
If you can see 20/15 or even better, this means that you are overcorrected. (It is not necessarily considered super-human acuity, but it is unnecessary to correct to this level.)
It is very difficult to perform Active Focus at this level of correction, as there is not enough of a blur horizon to produce stimulus - see Distance vision.