Ocular inflammation (4)
'ocular inflammation' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for stye that I've seen before include "Observer's problem" , "Eyelid infection" , "Eye complaint" , "Eyelid sore" , "makes viewer sore" .)
(Other definitions for iritis that I've seen before include "viewer's complaint" , "complaint of the eye" , "Eye inflammation" , "Complaint viewer has" .)