It's difficult to see if they are broken (7)
I believe the answer is:
glasses
'are broken' is the definition.
I can't tell whether this definition defines the answer.
'it's difficult to see if they' is the wordplay.
I cannot quite understand how this works, but
'it's' could be 'es' ('e' can mean 'electronic' which is similar to 'IT') and 'es' is found in the answer.
The remaining letters 'glass' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for glasses that I've seen before include "Specs" , "They make girls unattractive to Parker" , "Small refracting telescopes" , "Barnacles" , "Drinks" .)