A little round hole you can see through (5)
I believe the answer is:
pupil
'a little round hole' is the definition.
'pupil' can be an answer for 'hole' (pupil is a kind of hole). I'm not sure about the 'a little round' bit.
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for pupil that I've seen before include "bit of a looker" , "Schoolboy or eye part" , "One being taught" , "I learn" , "Eye opening" .)