Ummm..
have you ever considered the one contact lense strategy? I do a lot of diving where if I can't see my gauges, I am in trouble.....so I just got them at Costco. I have never worn glasses, this is like instead of reading glasses. I love it, it has solved a lot of issues for me.
I have the Garmin 305, but I don't think I could see the smallest numbers without the lense.