Sphere of vision (7)
I believe the answer is:
eyeball
'sphere of vision' is the definition.
Although both the answer and definition are singular nouns, I can't understand how one could define the other.
'sphere of vision' is the wordplay.
I cannot quite understand how this works, but
'sphere' could be 'ball' (ball is a kind of sphere) and 'ball' is located in the answer.
'vision' could be 'eye' (I've seen this in another clue) and 'eye' is located in the answer.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for eyeball that I've seen before include "Look confrontationally" , "Ocular orb" , "Confront (_____ to _____)" , "making us stare" , "Spherical optical organ" .)