Rarely do
migraine patients complain of losing vision in both eyes during an attack of
headache. There are no large clinic-based studies looking at the prevalence of
binocular blindness in
migraine sufferers and no information about patient demographics, neuroimaging, and laboratory testing.
METHODS: Over a 14-month time period, 383 new patients with a diagnosis of
migraine were seen at the Geisinger
Headache Center. All patients were asked if they ever experienced an episode of complete
bilateral blindness along with their
headaches. Those with a positive history had coagulopathy testing as well as brain magnetic resonance imaging and magnetic resonance angiography of the intracranial circulation.
RESULTS: A total of 6 patients or only 1.6% of the new
migraine patients had episodes of
binocular blindness with their
headaches. All were female and each had a history of
migraine for at least 3 years. Five patients had a diagnosis of
migraine without aura, while one had a diagnosis of
basilar-type migraine. In all patients the
blindness episodes occurred in isolation during a
migraine headache. In all but one patient the
blindness was instantaneous and not a slow evolution. In 2 patients the
blindness episode only occurred 1 time; in 3 patients episodes occurred more than once but were rare, while 1 patient had
blindness with 50% of her
headaches. In regard to duration, in 2 patients
blindness lasted only several seconds, 2 patients between 2 and 10 minutes, 1 patient 30 minutes and 1 patient 60-120 minutes. Neuroimaging was normal in all. Three patients had a history of smoking and 3 never smoked. Coagulopathy testing was abnormal in all patients. Two patients were homozygous for
methylenetetrahydrofolate reductase (MTHFR) 677TT polymorphism, but both had normal
homocysteine levels; 3 patients were heterozygous for MTHFR 677CT polymorphism and 1 had elevated
homocysteine levels and 1 patient had a positive
lupus anticoagulant (had the most frequent episodes of
blindness).
CONCLUSION:
Binocular blindness with
migraine headache is a very rare occurrence at least in a
headache specialty clinic population. It is a female-predominant event and occurs mostly in
migraine patients who do not have a history of
aura.
Blindness episodes can be very brief or prolonged and many do not fit the typical duration of a
migraine aura. They are typically infrequent events and may occur only 1 time without recurrence.
Migraine with
binocular blindness may reflect an underlying clotting disorder. A possible etiology outside of a coagulopathy-related event is
retinal spreading depression.