I heard ultimately charming young woman supplies optical equipment (8)
I believe the answer is:
'optical equipment' is the definition.
'i heard ultimately charming young woman' is the wordplay.
'heard' shows a homophone (sound like).
'ultimately' indicates one should take the final letters.
'young woman' becomes 'lass' (lass is a kind of young woman).
The final letter of 'charming' is 'g'.
'i' sounds like 'eye'.
'supplies' acts as a link.
(Other definitions for eyeglass that I've seen before include "Aid to vision" , "Monocle, or spectacles in plural" , "Lens for aiding defective vision" .)