Have you ever suddenly noticed shimmering lights, zigzag lines, or a strange blurry spot moving across your vision?
It can be pretty unsettling, especially the first time it happens. But in many cases, these temporary visual changes are something called a visual aura.
A visual aura most commonly associated with migraines, which is why they are sometimes called migraine aura.
Aura can cause flashing or shimmering lights, blind spots, geometric patterns, or other unusual visual effects. And despite the connection to migraine, you don’t necessarily have to develop a headache for it to happen.
Here’s what that can look like, why it happens, and how to know when a sudden change in your vision may be something else.
What Does a Visual Aura Look Like?
A visual aura can look a little different from person to person. Some people notice a small shimmering spot that gradually expands across their vision. Others see flickering lights, jagged patterns, or zigzag lines in vision.
You might notice a blurry or missing area, sparkles, geometric shapes, or colors that seem to move across your visual field. Some people describe the effect as kaleidoscope vision because the colors and patterns can resemble looking through a kaleidoscope or a prism.
So, what does a migraine aura look like compared with another unusual visual change?
One characteristic of a typical visual aura is that it often develops and changes over several minutes. You might notice a small spot near the center of your vision that slowly grows into a larger crescent or zigzag pattern before eventually moving out of your visual field.
You may also develop a blind spot, called a scotoma, that moves or expands as the aura progresses.
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Why Does Visual Aura Occur?
Even though you’re seeing something unusual with aura, the problem generally isn’t coming from your eyes.
Visual aura is thought to involve a wave of altered electrical and chemical activity that moves across the brain. When this activity involves the part of the brain responsible for processing vision, it temporarily changes what you see.
That’s why an aura in vision can cause lights, shapes, blind spots, or distorted images even when the structures of your eyes are completely healthy.
There isn’t always an obvious reason an aura happens. Some people notice episodes associated with:
- Stress
- Changes in sleep
- Dehydration
- Hormonal changes
- Skipped meals
- Bright lights
Others may experience them without identifying a consistent trigger.
Does a Visual Aura Affect One Eye or Both?
A typical visual migraine aura originates in the brain rather than the eye. Because of that, the visual disturbance is usually present in both eyes, although it may feel like it’s only on one side.
If it happens, try covering one eye and then the other.
If you can still see the pattern, flashing area, or blind spot regardless of which eye is covered, the disturbance is affecting both eyes. That is more consistent with a typical visual aura.
If the change is truly present in only one eye, that’s different and deserves further evaluation.
Can You Have a Migraine Aura Without a Headache?
Yes! An aura without headache occurs when you experience the neurological symptoms of a migraine aura but never develop the headache that people typically associate with a migraine.
This can be especially confusing if you’ve never considered yourself someone who gets migraines. But a headache isn’t required for a visual aura to occur.
What About an Ocular Migraine?
This is where the terminology can get confusing. People commonly use ocular migraine and visual migraine to describe the flashing lights, zigzags, or blind spots that occur with a typical migraine aura.
However, “ocular migraine” is also sometimes used when talking about retinal migraine, which is much rarer. It causes temporary visual changes or vision loss in one eye, rather than a visual disturbance coming from the brain and appearing in the visual field of both eyes.
If you’re experiencing a new visual disturbance in only one eye, it’s best to have your eyes evaluated.
How Long Does a Visual Aura Last?
A typical migraine aura generally develops gradually and lasts between about 5 and 60 minutes. During that time, the visual effects may move or change.
For example, a small shimmering spot may gradually grow into a larger pattern, move across your vision, and eventually disappear. Your vision should then return to normal.
If an episode lasts significantly longer than expected, comes on differently than your usual aura, or leaves you with a persistent change in vision, it should be evaluated.
Are Flashing Lights Always a Visual Aura?
No, and this is an important distinction.
Flashing lights in vision can happen with a migraine aura, but flashes can also originate inside the eye.
As the vitreous gel inside your eye changes, it can sometimes pull on the retina and create flashes of light. Occasionally, that pulling can cause a retinal tear, which can lead to a retinal detachment.
The pattern is often different from a visual aura. Migraine-related visual effects tend to develop gradually, move or expand, and affect the visual field of both eyes.
Flashes caused by the retina may be brief, repeated, and limited to one eye. They can also occur alongside a sudden increase in floaters or a shadow or curtain moving across your vision.
Sudden visual changes can also occasionally be related to neurological conditions, including a transient ischemic attack (TIA) or stroke.
That’s why a new visual symptom shouldn’t automatically be labeled a migraine aura based on what it looks like.
When Should You Have a Visual Aura Checked?
If you’ve experienced the same migraine aura for years and it has already been evaluated, you may become pretty good at recognizing your normal pattern. But a first-time visual aura is worth discussing with your eye doctor or healthcare provider.
You should also have symptoms evaluated if your usual aura suddenly changes, lasts longer than normal, or doesn’t completely resolve.
Seek urgent medical attention for:
- Sudden vision loss
- A curtain or shadow across your vision
- A sudden shower of new flashes or floaters
- Weakness or numbness on one side of your body
- Difficulty speaking
- Severe dizziness
- Other sudden neurological symptoms
When You’re Not Sure What You’re Seeing
The strange thing about a visual aura is that it can feel very much like something is wrong with your eyes, even though the visual changes are actually being generated by the brain.
For many people, migraine aura eventually becomes a recognizable pattern. But the first episode can be strange and sometimes pretty scary.
If you’re experiencing unusual lights, patterns, blind spots, or other changes in your vision, an eye exam can help us determine whether your eyes are healthy and whether another type of evaluation may be appropriate.
At Emerald Point Eye Care, we’re always happy to take a closer look and help you better understand what you’re seeing.
