"Yes, please. I have a suggestion. You said earlier on that all these modern glasses have the same prescription. Is it necessary to go back to my 20/20 vision? What happens if you pass me the next pair and I switch glasses straightaway?"
"In theory, there should be no problem. Let's give it a try but let me know if your eyes are giving you trouble. I don't want to take any risks with your eyes"
"Neither do I. But let's try it my way. It may save us a lot of time"