@Francois:: You've added a note describing a 'diopter ratio' as dividing left and right corrections (which would indeed be a mathematical ratio). However, I've got the impression that when Jake talks about 'diopter ratio' he might actually mean gap (difference). Eg https://endmyopia.org/the-diopter-ratio-trap-dont-favor-one-eye/
Important first point: The diopter ratio needs to stay the same throughout the prescription range. So whether you wear full, normalized, or differential, the difference between left and right eye diopter shouldn’t ever change.
seems to be mixing concepts of 'ratio' and 'difference'. That said, https://endmyopia.org/reducing-diopter-ratio-diy-patching-solution-pro-topic/ talks about the "percentage difference". There's also some threads on the forum which seem to use 'ratio' as 'gap'. Eg https://community.endmyopia.org/t/diopter-ratio-question/3695 Divenal (talk) 17:53, 31 July 2020 (UTC)
Thanks @Divenal:, I've added anote about the common usage of "ratio" as "gap" and added "difference" as a synonym. It's possible that making this distinction isn't super productive at this stage, but at the same time, it seems to be confusing a lot of the more mathematical-inclined people. --Francois (talk) 16:57, 1 August 2020 (UTC)