Good knowledge of english language is recommended, as is some technical flair. Requirements may vary somewhat from country to country, as do the procedures. See general info and contact national AOPAs for details. Yes, as a general rule. However, it depends on cause, nature and extent of required correction.
Normal myopia is no problem.
In doubt, check with an aeromedical doctor or the authorities in your country. AOPA Australia was heavily involved in this subject and probably has the best know-how. Flight Training is different, but not necessarily of lesser quality than in Europe. Quality levels are more uniform in Europe, while in USA the difference between good and bad may be much larger, and it is more difficult to evaluate and select a flight school thousands of kilometers away than just around the corner. Thus, the risk of losing time and money is higher.