this is not ophthalmology. this is neurology.
papilledema is 'swelling' of the optic nerve. it usually causes some pretty nasty vision loss...sometimes temporary, sometimes permanent. its not really an 'eye' problem...its a neurological one. it just happens to be obvious to someone who knows how to look at an optic nerve.
the prognosis is difficult to predict. papilledema is really a sign of a larger problem (tumor!)