Choose to get most of ice for drink dispenser (5)
I believe the answer is:
optic
'drink dispenser' is the definition.
(I've seen this before)
'choose to get most of ice' is the wordplay.
'choose' becomes 'opt' (I've seen this before).
'to get' says to put letters next to each other.
'most of' means to remove the last letter.
'ice' with its final letter taken off is 'ic'.
'opt'+'ic'='OPTIC'
'for' is the link.
(Other definitions for optic that I've seen before include "Picot (anag.)" , "Ocular" , "Teacher's maybe dispensed with this" , "Related to sight" , "connected to the eye" .)