Initially lacked everything near some part of the eye (4)
I believe the answer is:
lens
'the eye' is the definition.
(I've seen this in another clue)
'initially lacked everything near some part' is the wordplay.
'initially' says to take the initial letters.
'part' indicates taking the first letters.
The initial letters of 'lacked everything' is 'le'.
The first letters of 'near some' is 'ns'.
'le'+'ns'='LENS'
'of' is the link.
(Other definitions for lens that I've seen before include "feature of camera" , "Through which to view" , "Transparent optical devices" , "Piece of glass, usually curved" , "Piece of glass in optical instrument" .)