If you see shimmering zigzag lines or a spreading blind spot for 20 minutes and then feel perfectly fine, the most likely explanation is migraine aura without headache, often called silent migraine. But if this is new after age 40, or the symptoms hit suddenly rather than creeping across your vision, I treat it as a possible mini-stroke until proven otherwise.
A man in his late fifties sat in my office last year with his wife holding a printout of his smartwatch data. Three times in two months he had watched a glittering arc drift across his left visual field, then fade. No pain, no nausea. His family doctor had said “probably stress”; the eye clinic had found nothing; his wife was quietly convinced he was having strokes. Both of them were half right, which is exactly why this presentation deserves care.
What a silent migraine actually is
In the ICHD-3 classification, typical aura without headache is a recognised migraine subtype. The aura is the same wave of altered brain activity that precedes pain in classic migraine with aura, but the headache phase simply never arrives. Many people have had headache-associated aura earlier in life and notice the pain fading with age while the visual events persist. Others have never had a migraine headache at all.
The typical story is a visual disturbance that builds gradually over five minutes or more, often starting as a small bright spot that expands into a jagged, shimmering arc, and then fades within an hour. Tingling that creeps up a hand and into the face, or brief trouble finding words, can follow the same slow march. Some people feel a little tired or foggy afterwards. That slow spread and the glittering, positive quality (you see things that are not there) are the fingerprints of migraine.
The features that make me think stroke or TIA instead
A transient ischaemic attack usually behaves differently. Symptoms are most often negative, meaning something is lost: a patch of vision goes dark, an arm goes weak or numb, speech slurs. They tend to start abruptly, at full strength within seconds, instead of marching across over minutes. There is typically no shimmering or sparkling.
Context matters just as much as the symptom. First-ever aura after 40 to 50, a history of high blood pressure, atrial fibrillation, diabetes, smoking or high cholesterol, or aura that has changed in pattern recently all push me toward a vascular workup. I would not rely on a symptom description alone in that situation: it is reasonable to ask for brain MRI, imaging of the neck and head arteries, and a heart rhythm check. The same caution applies if you also have unexplained weakness, or if the episodes are all on the same side every time.
Two other look-alikes are worth knowing. Flashes or floaters in only one eye, especially with a curtain-like shadow, point to the retina and need a same-day eye examination; I discuss that overlap in my article on sudden one-eye vision loss. Brief, colourful, rapidly changing visual events lasting a minute or two can occasionally be occipital seizures, which an EEG helps sort out.
When it is migraine, what I actually recommend
Once stroke, retinal disease and seizure have been reasonably excluded, the treatment is often reassurance, because the episodes are harmless and short. A diary helps: record the time, duration, what the aura looked like and what preceded it. Sleep loss, skipped meals, dehydration, bright flicker and alcohol are common triggers. If you want a template, the headache diary guide is a practical start.
Triptans are not needed for an aura that ends by itself in under an hour. If the episodes are frequent or frightening enough to disrupt daily life, preventive options exist, and lamotrigine is the one with the most experience for aura specifically; that is a decision to make with your own neurologist. Hormones deserve a separate mention: because aura carries a modest stroke-risk signal, combined oestrogen-containing contraception should be reconsidered, as I explain in the birth control and aura guidelines article. If an MRI has shown small white spots, this piece on white matter lesions will put them in context.
The rule I give every patient
Go to an emergency department if any symptom comes on suddenly at full strength, if you have weakness, facial droop or slurred speech, if the aura lasts longer than an hour, or if it is your first one and you are over 40. A normal scan after a false alarm costs you an afternoon; a missed TIA can cost far more. If you have been dismissed with “it is just stress” and nothing has been properly checked, that is the situation I describe in Headache Not Getting Better? What Doctors Miss.
My patient’s workup came back clean: normal MRI, normal arteries, a regular heart rhythm, and a retina specialist’s all-clear. We labelled it aura without headache, adjusted his sleep and caffeine, and he has had one brief episode since. His wife stopped reading his smartwatch data.
Next steps: Download my free red-flag checklist to review your own symptoms, or talk to a specialist if your episodes are new, changing or unexplained.
Dr. Tae-Ho Guak, MD, is a neurologist with 25 years of clinical experience. This article is for general education and does not replace an examination by your own physician. If you have sudden weakness, speech trouble, facial droop or vision loss, call emergency services immediately.
From the textbook. Chapter 9, “Migraine With Aura and Its Subtypes,” of my clinical textbook Headache Medicine covers this topic in full for doctors, with the evidence and decision pathways behind it. About the book →