Migraine With vs Without Aura: Differences in Light Sensitivity & Light Triggers?

Written by Greg Bullock on 16th May 2019

We know that if you have any type of migraine, you are way more likely to have light sensitivity as one of your symptoms—even when compared with other chronic conditions. But there are subtle differences in photophobia for the approximately one-third of patients who also experience aura (visual or otherwise) with their attacks. We explore how light-related triggers and sensitivities might affect these individuals uniquely.

Similar levels of light sensitivity during and between attacks

Not surprisingly, the majority of clinical studies reveal the same conclusion: there is almost no difference in the percentage of migraine patients who experience light sensitivity—regardless of aura. In fact, between 85-95% of those diagnosed with migraine with aura report photophobia as part of their attacks, according to separate studies.^1,2 Additionally, the intensity of photophobic pain is equally prominent for all patients with the headache disorder, with well over three-quarters rating it as moderate or severe.³ Patients even share similar levels of light-related discomfort between migraine episodes as well.

Photophobia during the "aura" stage of attacks

If photophobia as a symptom is comparable during and outside of attacks, then what ARE the differences for a person with migraine-related aura? First, they experience an entire phase of migraine (the aura) that not every patient goes through, and it is a stage in which light sensitivity typically appears.

As a reminder, here are the four stages of a migraine attack:

Prodrome: Pre-attack experiences that begin a few hours or days prior to the episode
Aura: Also occurs prior to an attack, usually within the hour; roughly one-third of migraine patients have aura symptoms
Attack/Headache: The heavily symptomatic period which often features head pain (but not always) and can last from a few hours to several days
Postdrome: Describes the symptoms and issues that develop and/or persist after the main attack has subsided

Photophobia can be (and often is) a common complaint at all of these stages, but the aura stage presents its own challenges. Typically occurring 5 to 60 minutes before the headache sets in, the aura regularly develops with visual symptoms—ranging from zigzag patterns to temporary vision loss. Sensitivity to light is a large component of this stage as well, affecting perhaps as many as 88% of those who have migraine aura.³ This is more than any other issue during this time. And, as we noted, this often continues right into the attack stage, worsening the pain for the duration of the episode.

Curiously, one study showed a link between aura-related photophobia during an attack and more light sensitivity outside of one.¹ This could mean that light-sensitive migraine aura creates a greater risk for having photophobic reactions to light all the time. With interictal (or between-attack) visual discomfort levels being the same for those with and without aura, this might indicate separate biological causes, which we discuss in greater detail below.^4,5

Greater visual sensitivity and light-triggered pain for migraine aura

Although it is common for both groups, patients with migraine aura have generally been described as more visually sensitive to their environment. This can include intolerance to bright lighting, but it also encompasses sensitivity to stimuli such as flicker, glare or high-contrast patterns. In addition, this sensitivity may also extend to the eye-related symptoms (such as blurry vision, for example) that are hastened by environmental factors. And these findings remain consistent for episodic and chronic migraine with aura too.^6,7

Similarly, the triggering aspect of light also seems to more definitively affect patients with migraine-related aura. At least one study suggested that 40% believe that light exposure has brought on migraine with aura episodes when compared with just 5% of those without aura.¹ While we believe the latter number significantly under-represents how often light triggers attacks, this dramatic difference still must be recognized. And given the high percentage of aura patients who deal with visual complications during this stage, it makes sense that they might also be generally more sensitive to or prone to be triggered by their surroundings—including bright and/or flashing lights.

Unique brain activity for migraine aura & photophobia

Researchers have identified some unique brain effects related to aura that might explain these variance in light sensitivity and light triggers. One study showed a link between photophobia and elevated levels of a neurotransmitter called calcitonin gene–related peptide (CGRP). This has also been implicated in the broader migraine pathophysiology, but additional evidence suggests that those with migraine aura may have greater CGRP plasma levels. This could ultimately explain their greater risk for feeling light sensitive.^8,9

In addition, increased activity in the visual cortex of the brain has been recorded for people with migraine aura versus those without. This cortical hyper-reactivity may underlie prior findings that aura sufferers are more visually sensitive to their surroundings—particularly between attacks—and may explain why light is a more prominent attack trigger.¹ If true, this might also mean that different physiological processes affect those who do not have any aura symptoms; more specifically, certain pathways that lead to specific visual aura symptomatology may be distinct from those that actually lead to light sensitivity. As a result, this may also endorse more traditional explanations for migraine-related photophobia, especially during attacks, as common to all migraine types.

Lastly, some have theorized that this unique brain activity and the effects that result from it may make those with visual aura sensitivities more aware of how light impacts them. This can lead to a greater likelihood that they will report light sensitivity as a problem.

Where it all gets a little complicated

It is important to note that these differences are not clear cut. Doctors and patients often have a difficult time distinguishing between the timing of symptoms before an attack. Not only can patient recall and tracking be an unreliable measure, but we still do not know enough about the biological processes that lead to migraine and aura. This makes it a challenge to fully understand if certain symptoms are actually representative of the stage in which they are believed to occur. For example, some experts believe that sensitivity to light at any point prior to the onset of headache pain actually signals the earliest moments of the attack phase—not the prodrome or aura as we might expect.

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