While in Japan I bought some contact lenses, had to go to an optometrist. The bloke was great; I know whats up with my eyes since I've had glasses for 3 years, been looking into laser surgery for a while and when I applied for the AirForce was knocked back due to my sight and was given a pretty thourgh work-down medically. Basically in 10minutes the nurse moved me around the room and did the basics, reading a chart (which I might add is awesome, none of this letter junk, its a circle with a bit missing, like a C, and you say where the gap is, up, down, left, right) etc, then into the doc for a few minutes while he had a look for 2 mins.
Now for anything else... considering how little basic first aid any japanese person I've met knows I'd be looking for a foreign trained doctor.. plus theres the language barrier, if I'm sick I want it straight, not in Japanese where I may, in my hypothetical sick state, misinterpret what Im told or give bad information.