According to AMAS (and my AME) there is not a no fly period after single vision lens replacement There is a 6 month period where you must have glasses to correct the near vision eye for distance and then a medical flight test must be conducted. (Waiting to hear form FSDO on that) I currently use bifocals and they work fine. I tried prgressives and it was horrible. I just hate using glasses in general and if a permanent solution is available, i am interested. The doc gave me a near vision contact lens to try out for a day and it was ok, with the knowledge that the replacement lens will work better and feel better. It of course takes time to adjust to the monovison. I am hoping someone has done the same thing as what i am considering and can weigh in on their experience.