She studies part of the eye (5)
I believe the answer is:
pupil
'part of the eye' is the definition.
('pupil' is part of 'eye')
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for pupil that I've seen before include "part of my anatomy" , "Learner at educational institution" , "Centre of iris, in the eye" , "One in the eye or in place of learning" , "Learner in the eye?" .)