Eye's humorous though not front cover (6)
I believe the answer is:
ocular
'eye's' is the definition.
(I know this)
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for ocular that I've seen before include "Viewer" , "not to be seen - due to this trouble?" , "Of the eye - visible" , "connected with 23 [SIGHT]" , "Eyepiece" .)