It's not uncommon for migraines to make you sensitive to light or leave jagged lines across your field of view. But some patients experience the visual symptoms of migraine without the headache. These "visual migraines" have recently been linked to a heart abnormality known as Patent Foramen Ovale (PFO).

PFO is a birth defect in which the walls between the two upper chambers of the heart don't close completely. An estimated 1 in 5 adults have PFO but since the defect doesn't typically cause symptoms, many people may not discover they have the defect until they're struck with a transient ischemic attack, or a stroke lasting under 24 hours. Fortunately less than 1% of people with PFO experience these strokes as a result of this defect.

In patients with this disorder, the opening between the chambers of the heart can either be a right to left shunting or a left to right shunting. Right to left shunting is considered more dangerous than left to right, and has been associated with migraine with aura.

In a new study, patients with visual migraines alone experienced a decrease in symptoms after receiving a surgery to close the opening.  For 80% of those patients, these improvements developed into full relief of symptoms after one year. The surgery relieved symptoms for 52% of  patients with migraine with visual aura and for 75% of patients who had both migraine and visual aura but didn't experience them simultaneously.

The results suggest a strong association between visual aura symptoms and PFO. While a heart defect may not be causing your migraines with aura,  it's important to consider the possibility if you have experience with transient ischemic attacks or have been diagnosed with PFO.

References

Khessali, H. The effect of patent foramen ovale closure on visual aura without headache or typical aura with migraine headache.  J Am Coll Cardiol Intv. 2012;5(6):682-687. doi:10.1016/j.jcin.2012.03.013

"Patent Foramen Ovale (PFO)." Cleveland Clinic. Accessed July 4, 2012. http://my.clevelandclinic.org/disorders/patent_foramen_ovale_pfo/hic_patent_foramen_ovale_pfo.aspx.