In this type of migraine
, there is a loss of a portion up to all of the vision
of 1/2 of the field of vision of both eyes (check by covering one eye
and then the other).
Usually the greyed out loss has a shimmering surround which flickers until it disappears. These type of migraines are benign, short lasting (usually less than an hour), and cause no permanent change. No worry unless frequent.