I mention sound or vision (8)
I believe the answer is:
eyesight
'vision' is the definition.
(eyesight is your vision)
'i mention sound' is the wordplay.
'i' becomes 'eye' (I've seen this in other clues).
'mention' becomes 'cite' (to cite is to mention or quote).
'sound' indicates a 'sounds like' (homophone) clue.
'cite' is a homophone of 'sight'.
'eye'+'sight'='EYESIGHT'
'or' is the link.
(Other definitions for eyesight that I've seen before include "View" , "Requirement to look" , "perception" , "Power of seeing" , "Visual faculty" .)