Do eyeglass prescriptions make a normal distribution? If you measured that you could produce a whole bunch of lenses following the distribution.
Then I wonder if you could loosen tolerances in your production process so that the lenses produced follow the prescription distribution in the population. If you can loosen tolerances like that you can potentially save $$$.
Now you have a bunch of lenses whose distribution matches the population. At this point, could the people who need these lenses not simply walk up and try on glasses until a matching pair is found?
Then I wonder if you could loosen tolerances in your production process so that the lenses produced follow the prescription distribution in the population. If you can loosen tolerances like that you can potentially save $$$.
Now you have a bunch of lenses whose distribution matches the population. At this point, could the people who need these lenses not simply walk up and try on glasses until a matching pair is found?