I knew some people would think my post in error.
...
In Japan neither chiropractors nor seitaishi are doctors. That isn't to say that a person might not obtain a doctor of chiropracty license abroad and practice in Japan, though.
Same goes for chiropractors:
http://www.ccv.ne.jp/home/hcc/7faqshikaku.html#anchorseitai3
A person may obtain optometry training in Australia and work in Japan. But the same could be said for a person who hasn't obtained the training anywhere. There is no special educational or licensing requirement equivalent to "Doctor of Optometry".
http://tinyurl.com/l54x7