Viewer's complaint about something done on pitch (8)
I believe the answer is:
cataract
'viewer's' is the definition.
Although both the answer and definition are singular nouns, I can't see how they can define each other.
'complaint about something done on pitch' is the wordplay.
'complaint about' becomes 'ca' (this could be a standard abbreviation of which I'm unaware).
'something done' becomes 'act' (I've seen this before).
'on' means one lot of letters go next to another.
'pitch' becomes 'tar' ('tar' can be a synonym of 'pitch').
'act' put after 'tar' is 'taract'.
'ca'+'taract'='CATARACT'
Can you help me to learn more?
(Other definitions for cataract that I've seen before include "Waterfall which might be seen in the eye" , "Force" , "what may have a bad effect on the viewer" , "big water surge" , "Waterfall - eye complaint" .)