As the cataract surgery
is done only under local anaesthesia, the surgery or the anaesthesia per say doesn't have any effect on the body metabolism
or the nervous system.
Though change in posture, lying down for long hours and anxiousness of surgery can cause dizziness.
can be the reason.
Get her to drink plenty of fluids, have regular meals, and get ample rest.
Stand up slowly as this may help dizziness associated with position changes.
Reassurance can also help to relieve her of anxiety.
Wishing your wife good health and early recovery.