Automated self service eye exam

  They have machines that do your blood pressure for free, so why not a machine that is for people who have trouble seeing and buy over the counter glasses? Yes, you can go to the eyeglass place and get a free eye exam, but then you have to pay outrages prices for frames. Why can't they have a machine that people can go up to and do a short eye test to see what strength of over the counter glasses they need?
  The reason I thought of this is because my husband wears prescription glasses and we can't afford to get another pair right now and medicaid only pays for 1 pair every 5 years for adults. We are not sure what strength of glasses he needs and it would be neat if we could go into a lets say Walmart and he could do a short eye test and get a 5 dollar pair of glasses. This could benefit kids and adults who are rough on glasses and do not want an expensive pair of glasses.