Recognising letters there reveals strength of vision (8)

'recognising letters there reveals strength' is the definition.
I don't know anything about this answer so I cannot judge whether it can be defined by this definition.

'vision' is the wordplay.
I cannot quite see how this works, but
'vision' could be 'eye' (I've seen this in another clue) and 'eye' is located in the answer.
The remaining letters 'chart' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...

'of' acts as a link.

Can you help me to learn more?