After donating plasma, i experienced brief xanthopsia before passing out. is this normal?

Possibly: Xanthopsia is a very rare. It is most commonly associated with digitalis overdose but has been reported in vitamin deficiencies, jaundice, or cataracts. None of these would be transient. You should not be passing out after plasma donation- that needs to be check by a doctor. Vision changes before passing out could be due to loss of blood supply to brain or to a brief seizure - get checked