Eye or heart (6)
I believe the answer is:
centre
I believe this clue is a double definition.
'eye' is the first definition.
('centre' can be a synonym of 'eye')
'heart' is the second definition.
('centre' can be a synonym of 'heart')
'or' is the link.
(Other definitions for centre that I've seen before include "and this may follow 26, 25 [LEFT RIGHT]" , "Point equidistant from all other points" , "Heart" , "Nucleus" , "'Things fall apart; the ... cannot hold'/Yeats" .)