Cornea neighbor (6)
I believe the answer is:
sclera
'cornea neighbor' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for sclera that I've seen before include "Eyeball's outer cover" , "Membrane" , "Bit of a looker" , "tissue in the eye" , "part of the eye" .)