Inflammation found in crusty eyes (4)
I believe the answer is:
stye
'inflammation' is the definition.
(I've seen this before)
'in crusty eyes' is the wordplay.
'in' says the answer is hidden in the clue.
'STYE' is hidden in the letters of 'crusty eyes'.
'found' is the link.
(Other definitions for stye that I've seen before include "Eye sore" , "Climb" , "Infection on the edge of the eye" , "Infected swelling of the eye" , "Observer's problem" .)