I often meet with children in my clinic who report having temporary blind spots in their vision, that seem to grow in size. This can be a frightening experience! Children and their parents are often worried about a severe eye problem in this scenario, particularly if no one in the family has ever experienced similar symptoms.
Fortunately, the eye exam in this setting is almost always normal. How can this be, one might ask? It's because a very common cause of this symptom is migraine, which is a headache syndrome. The root of the problem originates in the brain, not in the eyes -- so the eye exam is normal. The visual symptoms that many people experience with migraine headaches are called "auras."
Migraine headaches are common in children and adolescents, and often follow a course something like this: the person notices a small smudge in their vision, which over the course of a few minutes, expands in size to cover most of their field of vision in both eyes. The edges of this blind spot are often shimmering zigzags, sort of like looking through a kaleidoscope. This aura slowly recedes, and a headache then follows. The headache is often severe, and may be associated with sensitivity to bright lights or loud noises, and the person may be nauseated. Roughly 30% of migraineurs will experience an aura before their headache; sometimes the aura may occur by itself, without a headache.
I recently met a very sharp young patient named Brooke who gave me permission to share her story. She was experiencing frequent blind spots in her vision, and she and her mother were understandably worried by them. I asked if her blind spot started small, like a smudge, and then gradually grew. She nodded. I asked if the edges were shimmering zigzags. She nodded again. I asked if the spot then went away slowly and if she got headaches around the same time. Her eyes got big, she smiled, and said, "You get me!"
To my delight, she then pulled out some drawings that she had made of the vision changes that she gets with her migraine headaches. As a frequent migraineur myself, I found them strikingly accurate. She kindly gave me permission to share them here, so that others could learn about them.
Interestingly, not all auras are visual; some patients experience sensory auras involving a pins-and-needles feeling in the arms or face, which may be followed by numbness.
Patients with visual symptoms followed by headache should consult with their primary doctor. If the primary doctor has concerns about the possibility of a visual problem, a referral to an eye doctor can be pursued.