Work revising the school map: it’s for examining pupils (14)
I believe the answer is:
ophthalmoscope
'it's for examining pupils' is the definition.
(an ophthalmoscope is used to examine eyes)
'work revising the school map' is the wordplay.
'work' becomes 'op' (abbreviation for opus).
'revising' indicates anagramming the letters.
'the'+'school'+'map'='theschoolmap'
'theschoolmap' with letters rearranged gives 'hthalmoscope'.
'op'+'hthalmoscope'='OPHTHALMOSCOPE'
(Other definitions for ophthalmoscope that I've seen before include "Instrument for inspecting the retina and other eye parts" , "Optical instrument" .)