You're quietly reading or looking at a screen, when suddenly... flashing shapes or light zigzags appear in your field of vision. And yet, unlike a classic migraine, you feel no pain. What do these impressive but painless visual phenomena mean? They're often referred to as non-migraine visual auras or ophthalmic flickers.
What is a visual aura?
A visual aura is a temporary disturbance of vision, often characterized by:
- Flashes of light, zigzags or fortress-like patterns (often C-shaped).
- Flickering spots or blurred areas.
- Blurred or partially obstructed vision.
These manifestations generally last between 10 and 30 minutes, then disappear on their own. When they occur without head pain, we speak of an isolated visual aura or migraine without headache.
Is it dangerous?
In the majority of cases, these phenomena are benign, especially if they occur occasionally. They are linked to temporary electrical activity in the brain's visual cortex. However, if you're experiencing this kind of episode for the first time, or if they become more frequent, it's important to consult a vision care professional to rule out other causes.
What are the possible causes?
Here are some triggers or causes associated with light zigzags without migraine:
- Eye fatigue or visual stress (screens, prolonged reading)
- Hormonal changes
- Low blood pressure
- Hypoglycemia
- Certain circulatory or neurological abnormalities (rarer)
- Migraine disorder without headache (diagnosis by exclusion)
When to consult?
We recommend that you see an optometrist if you:
- Are experiencing this type of phenomenon for the first time.
- Note an increase in frequency or intensity.
- Have other associated symptoms: vision loss, difficulty speaking, numbness, etc.
- Have a history of eye problems or cardiovascular disease.
Seeing light zigzags without having a headache can be disconcerting, but it's not necessarily cause for concern. In many cases, it's a benign neurological phenomenon. However, professional advice will give you a better understanding of what's going on and ensure that there's nothing more serious involved.
