Hi KKPurple
If the surgery you have had has improved your condition and therefore the amount of help you need, then you have to report it to the DWP. If the surgery has had no impact on the aids and support you need, you don't have to inform them of the surgery (unless you were in overnight for 28 days - which, for cataracts, you wouldn't have been.)
BIS
Nothing on this board constitutes legal advice - always consult a professional about specific problems