Surveillance needs excellent eyesight (11)
I believe the answer is:
supervision
'surveillance' is the definition.
(thesaurus)
'excellent eyesight' is the wordplay.
'excellent' becomes 'super' (I've seen this before).
'eyesight' becomes 'vision' (I've seen this before).
'super'+'vision'='SUPERVISION'
'needs' is the link.
(Other definitions for supervision that I've seen before include "Control" , "Oversight" , "provided by the boss" .)