Geographically, Asia comprises of approximately fifty countries in the regions of Central, East, South, Southeast, and Western Asia, and parts of Eurasia. However, in European languages the term “Asian” more commonly refers to ethnic heritage rather than a strict geographic area. In American English, “Asian” often refers to East Asians, while in British English, Asian often refers to South Asians.
The Orient is the East, traditionally comprising anything that belongs to the Eastern world, in relation to Europe. In English, it is largely a metonym for, and coterminous with, the continent of Asia (reference: https://en.wikipedia.org/wiki/Orient). The term Eastern World originally had a literal geographic meaning. It contrasted Asia with the cultures and civilizations of Western Europe (reference: https://en.wikipedia.org/wiki/Eastern_world).
An author needs to be aware of different interpretations of these terms by different audiences before using the terms in academic writing.