Reporter's relatively hackneyed cover for The Observer (6)
I believe the answer is:
cornea
'observer' is the definition.
Although both the answer and definition are singular nouns, I cannot see how they can define each other.
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for cornea that I've seen before include "Transparent part of the coat of the eyeball" , "seen through by pupil" , "Membrane of the eye" , "Front covering of eye" , "Body part" .)