The word "retroiridian" is spelled re-tro-irid-i-an. The pronunciation is /ˌretroʊɪˈrɪdiən/. This term refers to something that is situated behind the iris. The prefix "retro-" means behind, while "iridian" relates to the iris of the eye. The spelling follows English conventions, with the emphasis on the second syllable, and the use of the letter "i" after the "r." While not a commonly used word, it is important for those in ophthalmology or related fields to know.
Behind the iris.
A practical medical dictionary. By Stedman, Thomas Lathrop. Published 1920.