Perused the letter preserved (7)
I believe the answer is:
scanned
'perused' is the definition.
The answer and definition can be both to do with perception as well as being past participle verbs.
Perhaps there's a link between them I don't understand?
'letter preserved' is the wordplay.
'letter' becomes 's'.
'preserved' becomes 'canned' (canning is a kind of preserving).
's'+'canned'='SCANNED'
'the' is the link.
Can you help me to learn more?
(Other definitions for scanned that I've seen before include "given thorough examination" , "Thoroughly examined" , "examined closely" , "Glanced over" .)