I'm calling shenanigans on this.
During my stroke last year blood around my brainstem was pressing up against my optic nerve. While things improved a bit after the bleeding receded, here 2 years after the stroke I'm still having significant issue with double vision, blurred vision, issues with focusing, trouble with saccadic movement, and all sorts of other issues.
It's continued to get a bit better with constant visits to a vision therapist and neuro-ophthalmologist... But it's never fully going to get better...
And, I'm definitely extremely skeptical of anything that says that it can "correct vision..." since generally it usually means "regular issues with vision."