Bryan Caplan recently asked for one good reason why basic eye exams can't be done by machine. I.e., why a machine can't ask "better like this, or like that?"
Computerized eye testing is probably a little different than what Caplan imageined. The shopkeeper (not a medical doctor) is still asking you "better like this or like that?" and replacing lenses, as directed by the computerized system. Labor is cheap enough over here that real robotics won't be economical for a while.
Something I've learned is that whenever you want to ask questions or make assertions about the medical system in the US, go look at the medical system in India. You are likely to be very surprised. Other claims that India disproves are "medical consumers can't price shop" and "hospitals will never post their prices".