How migraine affects vision during the migraine aura:
Kathleen Digre, MD is a Professor of Neurology & Opthamology at the University of Utah. She also is the current President on the American Headache Society and a widely respected headache and eye specialist.
- 1 Common visual disturbances include:
- 2 What is the migraine aura?
- 3 Diagnosing Migraine with Aura
- 4 Classifications of Migraine with Aura
- 5 What about Ocular, Optical & Ophthalmic migraine?
- 6 Migraine Aura Symptoms & Classification Summary
- 7 Causes of Migraine Aura
- 8 The Most Dangerous Aspect Of Migraine Is Aura
- 9 Migraine Aura Triggers
- 10 Treatment Of Migraine With Aura
Okay, so one thing we have to understand is that people who have migraine with aura have a specific kind of migraine. It’s usually heralded by a visual symptom, which we call aura, and it’s a discreet neurologic event that causes disturbance in the vision.
And it often will start little. Just almost like a little flickering or almost kaleidoscopic, and then it will build up and grow. And what some people think is something is wrong with their eye, but really it’s happening in the brain, and if they cover the eye that they think has it, they can still see the little zig-zaggy lines or spots on the page in the other eye.
So we know that it’s coming from the brain. We know also, or we think we know, that it is triggered by cortical spreading depression. When they’ve done experiments looking at the brain and the slow waves that travel in the brain, the speed with which that slow wave travels corresponds a lot with the aura and scientists have figured that out.
The aura frequently will come before the headache and then the person will have a headache. Sometimes it’s on the opposite side to the visual symptoms, sometimes it’s on both sides, and then the headache can be indiscernible from a migraine without aura. But an aura is a discreet neurologic event, usually visual.
There are other types of auras, such as dizziness or vertigo auras, or numbness around the face and hand followed by a headache, but the visual aura is the most common.
What’s interesting about this aura is as people get older, sometimes they lose the headache but keep the aura, and sometimes that is called later-life migraine accompaniments. It’s still a migraine aura, but it doesn’t trigger the headache.
What I think is also interesting about people with migraine with aura and with people with migraine, in general, is that in-between their big headaches, they’re also visually sensitive, so they’re always a little bit more light-sensitive than the next person. And we talked about light sensitivity last year. But also visually sensitive to stripes, flickering lights, lights that are moving.
Peripheral movement in the visual field will sometimes even trigger a migraine. Bright lights could trigger a migraine. People with migraine, in general, are very visually sensitive people.
There are some people with migraine that can also get other visual phenomena. For example, there’s an entity that we’ve come to call visual snow. Visual snow is very different from an aura. Remember I said the aura was a discreet neurologic event that occurred, followed by the headache.
Visual snow is a persistent visual phenomenon. It’s like little itty-bitty, tiny dots that are there, like in the old TV sets. Do you remember old TV sets? They’d have that snowy pattern. Well, people see it all the time and they can see through it. So their vision can be 20/20. It can be perfect vision, but they continuously see these little visual dots. Some people have blobs of colour that they continuously see.
I’ve seen people who feel like they see little things floating around. People with migraine can have floaters. You can have floaters. Lots of people have floaters and floaters just float in your vision, but people with migraine seem to notice those floaters a little bit more readily and can actually see them easier, especially on a blank wall or in the blue sky you can see your floaters better.
And then people with migraine also have funny symptoms. They can look at an object, and then they can look away and they might see the same object sitting next to them, and that’s called palinopsia. Or they can have their hand go in front of a target and they can almost see their hand moving across space.
So it’s these sort of funny visual phenomenon that people with migraine are more prone to, which makes it very interesting but also challenging in patients who have it to describe these phenomenon that are so different from our normal visual world to, for example, your ophthalmologist or your eye doctor.
Migraine with aura is characterized by temporary symptoms known as the ‘aura’ which typically develop prior to a migraine attack. An aura may occur before or during the head pain from a migraine attack.
Migraine with aura is experienced by around 5% of the general population. (1)
An aura may not be present with every attack. Only 19% of those with migraine experience an aura with every migraine. A further 30% of patients will experience migraine aura with some of their attacks. (1)
Most people associate migraine aura with visual disturbances.
Common visual disturbances include:
- Colored spots.
- Flashing lights.
- Tunnel vision.
- Zig zag lines.
- Blind spots.
- Temporary blindness.
- Distortions in the size & shape of objects.
- Vibrating visual field.
- Heightened sensitivity to light.
- Shimmering pulsating patches or curves.`
Other aura sensations include:
- Abdominal symptoms such as nausea or a rising sensation in the stomach.
- Sudden anxiety or fear.
- Feeling separated from your body.
- Sensation of limbs or teeth growing.
- Feeling overheated.
- Confusion, reduced mental cognition, forgetting common words or how to do simple tasks.
What is the migraine aura?
For those who experience migraine aura, it often signals an unmistakable warning of an impending migraine attack. Most commonly, an aura is a visual arc of scintillating, shining spots or shapes which begin in a small area of your central vision and gradually expand peripherally. (3)
This movement across the visual field is attributed to a cortical spreading depression (CSD). CSD is a wave of electrically excitable neurons and their surrounding cells depolarising. The cells which are normally negatively charged become positively charged. What follows is a period of suppressed neural activity. Neural activity is believed to be the physical basis for thoughts, feelings, and perceptions.
For most people auras last 5-60 minutes which is usually followed by a moderate to severe head pain that characterizes migraine.
Types of Migraine Auras
Visual symptoms are felt in around 86% of those who experience a migraine with aura. There are also other types of migraine auras which are generally less well known.
These include ‘sensory aura’, ‘language aura’ and ‘motor aura’.
In the same way a visual aura causes all sorts of disruption to vision, the sensory aura disrupts other senses. Smell, touch and hearing impairment or disruption are symptoms of the sensory aura.
Language aura refers to when speech and language systems are disrupted. Symptoms include difficulty speaking and finding the right word(s).
Motor aura results in muscle weakness or paralysis to one area or side of the body.
Retinal migraine is a subtype of migraine with aura where a visual aura occurs in one eye. The migraine patient may or may not experience head pain as part of their attack during a retinal migraine.
Migraine with aura or migraine without aura are the two main categories of migraine classified by the International Classification of Headache Disorders (ICHD). In the latest edition ICHD III, there was an update to the classifications to include another type of aura called ‘migraine with brainstem aura’. (2)
A brainstem aura involves symptoms that originate from the brainstem. These include vertigo, slurred speech, double vision, reduced level of awareness or alertness.
From 2,030 patients on the Headache Registry Database at the Mayo Clinic (1) the following incidence of auras were found amongst clinic patients (see chart).
Brainstem aura data was not available from the Mayo Clinic.
Diagnosing Migraine with Aura
ICHD III criteria for migraine with aura is:
A) At least 2 attacks fulfilling criteria B and C
B) 1 or more of the following fully reversible aura symptoms:
- Speech and/or language
C) At least 3 of the following 6 characteristics:
- At least one aura symptom spreading gradually over 5 minutes.
- Two or more aura symptoms occurring in succession.
- Each individual aura symptom lasting 5-60 minutes.
- At least one aura symptom is unilateral.
- At least one aura symptom is positive.
- The aura is accompanied, or followed within 60 minutes, by headache.
D) Not better accounted for by another ICHD-3 diagnosis.
Classifications of Migraine with Aura
There are 4 types of migraine with aura according to the new classifications from ICHD III. These are:
- Migraine with typical aura
- Migraine with brainstem aura
- Hemiplegic migraine
- Retinal migraine
Migraine with typical aura
The first classification is a migraine with typical aura. This occurs when an aura has visual, sensory or language symptoms, but no motor, brainstem or retinal symptoms. Most patients with aura fall into this category unless there is a category which better fits their symptoms.
Migraine with brainstem aura
This type of migraine is where an aura may have visual, sensory and language symptoms but no motor or retinal symptoms. Brainstem aura is diagnosed is an aura with both:
1) At least two of the following symptoms:
- Slurred speech
- Tinnitus or ringing in the ears
- Hearing disruption or impairment (not including ear fullness)
- Double vision
- Decreased control over bodily movements
- Decreased level of consciousness
2) No motor or retinal symptoms.
Not all symptoms are listed here but brainstem auras can cause what feels like very strange outer body experiences. Sometimes it is referred to as ‘Alice in Wonderland syndrome’ which is a rare but distinctive distortion of body image and perspective. This syndrome can occur at any age and is thought to be more common amongst children.
This type of migraine is distinguished by a single characteristic which is motor weakness. Hemiplegic migraine patients will experience an aura which may also include visual, sensory or language symptoms. To be classified as a hemiplegic migraine, motor weakness such as muscle weakness and inability to move certain areas or an entire side of the body must be experienced. Hemiplegic migraine can render an individual temporarily paralyzed with stroke-like symptoms.
Retinal migraine is where a visual aura occurs in only one eye. A distinguishing feature of retinal migraine is that they may or may not include the head pain from a migraine. It may simply involve an aura which may last 5-60 minutes in one eye without head pain from a migraine attack.
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What about Ocular, Optical & Ophthalmic migraine?
You might have heard about ocular migraine, optical migraine or even ophthalmic migraine. These are terms which may be used to describe your migraine condition by others but they are not formally recognized migraine classifications by the International Headache Society or the International Classification of Headache Disorders.
Often these are terms used by individuals or doctors who are not aware of the ICHD classifications (unfortunately this is more common than you think). The terms are essentially translated to “eye or eye-related migraines” which isn’t a particularly helpful diagnosis. The reality is many general doctors may not aware of the globally recognized standard of migraine classifications.
There is no classification for ocular, optical or ophthalmic migraine under the current ICHD-3. When someone claims they have an ocular, optical or ophthalmic migraine, then sees a qualified doctor to get an official ICHD diagnosis it is likely to fall into one of the four types of migraine with aura discussed above.
Which type of migraine with aura will depend on the symptoms experienced and diagnosis from your doctor. Below is a symptom & classification table to help you get a headstart.
Migraine Aura Symptoms & Classification Summary
Causes of Migraine Aura
Migraine aura is believed to be caused primarily by the cortical spreading depression (CSD).
Brain cells use electrical ions around the cellular membrane to maintain equilibrium. In aura, there is a temporary malfunction of this cellular balance which causes a wave of electrical disturbance, the CSD.
This wave of intense excitation across the visual cortex is what is thought to lead to visual aura symptoms including shimmering patches or curves, stars or blind spots etc. After the wave passes it could also cause an abnormal inhibition of activity which may explain the blind spots, partial or temporary blindness.
Neuroimaging studies show evidence that CSD leads to a decrease in blood supply to certain areas in the brain. The lack of blood supply and the electrical disruptions may account for the wide and varied range of symptoms. It may also help explain differences that can be experienced by the same individual on different occasions.
Why some people have aura and others don’t is likely due to several anomalies that researchers don’t yet fully understand. It is hypothesized that there are several genetic factors that play a role in a patient’s predisposition to migraine with aura. Research is taking place to understand potential genes involved in aura which will hopefully lead to specific treatments to prevent aura.
The Most Dangerous Aspect Of Migraine Is Aura
Migraine aura is perhaps the most dangerous part of a migraine attack for two reasons.
Firstly, the restriction of blood supply to brain cells can potentially lead to the damage or death of these cells.
Secondly, a mini-stroke or transient ischemic attack (TIA) can be mistaken by someone with migraine as “just another aura”. (4)
Symptoms of TIA are similar:
- Weaknesses, numbness or paralysis of the face, arm or leg on either or both sides of the body.
- Difficulty speaking or understanding.
- Dizziness, loss of balance or unexplained fall.
- Loss of vision, sudden blurred or decreased vision in one or both eyes.
- Headache, usually severe and of abrupt nature or unexplained change in the pattern of headache.
- Difficulty swallowing.
A TIA is a dangerous precursor to a full-blown stroke. (5) These are life-threatening events which can lead to permanent disability or death. Knowing the difference between a TIA and migraine aura is important.
The key differentiator is the ‘slow march’ of spreading symptoms that reflect the CSD which is characteristic of a migraine aura. With stroke it tends to be sudden and intense almost immediately or very quickly. Another way you might distinguish a migraine aura from a TIA is by noticing your typical duration of aura symptoms with complete resolution generally within the hour.
If there is any uncertainty or anxiety about your condition you should see a doctor to confirm your diagnosis. A physical exam, CT scan or MRI may be used if appropriate to rule out other underlying conditions. This is a good idea if you’ve experienced your first aura after age 40, and when your aura symptoms are very brief (less than 5 mins) or unusually long (over 1 hr). It’s better to be safe than sorry.
Migraine Aura Triggers
Triggers for migraine with aura are similar to other classifications of migraine. Triggers vary widely amongst individuals. Common triggers include:
- Sleep deprivation or disruption.
- Visual strain, bright or flickering lights.
- Neck stiffness or pain.
- Caffeine changes.
- Diet – including common trigger foods.
Those with migraine are strongly advised to keep a migraine diary to keep track of triggers, symptoms and help evaluate the effectiveness of treatment for your condition.
Treatment Of Migraine With Aura
A comprehensive treatment plan is required for migraine with aura to help take control and reduce your attacks.
Reducing migraine is especially important for migraine with aura due to the potential risks from frequent and severe auras over an extended period of time. Studies have shown an association between migraine with aura and stroke. (6) If you experience migraine with aura and take oral contraceptives your risk may be even higher. (6) This is something to speak to your doctor or specialist about.
Unfortunately good treatment results can be difficult to achieve in severe cases of migraine. Migraine globally is undertreated and poorly managed. (7)
Rarely does a miracle solution present itself as a miracle pill or cure. More often it is the result of an educated partnership between patient and doctor which results in a comprehensive evaluation and adjustment of behavioral, dietary and lifestyle factors which are supported where appropriate with acute and preventative treatments.
Let me know your aura symptoms in the comments below.
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1) DeLange, Justin M., and F. Michael Cutrer. “Our Evolving Understanding of Migraine with Aura.” Current pain and headache reports 18.10 (2014): 1-13.
2) Headache Classification Committee of the International Headache Society (IHS). The International Classification of Headache Disorders, 3rd edition (beta version). Cephalalgia. 2013;33:629-808.
3) Buzzi, M. Gabriella, and Michael A. Moskowitz. “The pathophysiology of migraine: year 2005.” The journal of headache and pain 6.3 (2005): 105-111.
4) Easton, JD; Saver, JL; Albers, GW; Alberts, MJ; Chaturvedi, S; Feldmann, E; Hatsukami, TS; Higashida, RT; Johnston, SC; Kidwell, CS; Lutsep, HL; Miller, E; Sacco, RL; American Heart, Association; American Stroke Association Stroke, Council; Council on Cardiovascular Surgery and, Anesthesia; Council on Cardiovascular Radiology and, Intervention; Council on Cardiovascular, Nursing; Interdisciplinary Council on Peripheral Vascular, Disease (Jun 2009). “Definition and evaluation of transient ischemic attack: a scientific statement for healthcare professionals from the American Heart Association/American Stroke Association Stroke Council; Council on Cardiovascular Surgery and Anesthesia; Council on Cardiovascular Radiology and Intervention; Council on Cardiovascular Nursing; and the Interdisciplinary Council on Peripheral Vascular Disease. The American Academy of Neurology affirms the value of this statement as an educational tool for neurologists.”. Stroke; a journal of cerebral circulation 40 (6): 2276–93.
5) Johnston, S. Claiborne, et al. “Validation and refinement of scores to predict very early stroke risk after transient ischaemic attack.” The Lancet 369.9558 (2007): 283-292.
6) Etminan, Mahyar, et al. “Risk of ischaemic stroke in people with migraine: systematic review and meta-analysis of observational studies.” Bmj 330.7482 (2005): 63.
7) World Health Organisation. Lifting the Burden. ‘Atlas of headache disorders and resources in the world 2011.’ WHO Press. 2011.
3rd aura image: Kronos (https://commons.wikimedia.org/wiki/User:Kronos)