You think -7 diopters is strong? I was at -19.75 diopters. Had bad eyes for a long time, since early childhood. Had to wear contact lenses starting at age 13. Wore them for fourty years, starting with "hard" lenses and changing to gas permeables later on. Soft lenses just would not do the trick. More recently I was diagnosed with the start of cataracts. I underwent eye surgery on both eyes where the normal crystalline lens is removed and a plastic implant lens is installed. The difference was like night and day. I have to wear glasses for closeup work but even with contacts I still needed reading glasses. I was back on the bike a couple of days after surgery. Since I also have macular degeneration I have to be vigilant of retinal detachment but so far it has been smooth sailing.

'bent Brian