Visual stimuli are common triggers of migraine and are associated with pattern glare.

Objective: To investigate the associations between interictal pattern glare, visual stress, and visual triggers of migraine.

Background: There has been relatively little research on the visual stimuli that can trigger migraine episodes. This is surprising, since if practitioners can obviate such triggers, then some attacks may be prevented. The existing literature suggests that patients who are prone to visually triggered migraines report more illusions on viewing striped patterns ("pattern glare") and that colored filters may be an effective intervention for these people.

Methods: Headache symptoms and headache triggers were investigated in migraine and control groups in 2 separate experiments. In one experiment, we also determined, for each participant, pattern glare, whether it was reduced by colored filters and, if so, what the optimum color of filter was. Color vision was also assessed with the D15 test.

Results: People with migraine saw significantly more illusions on viewing each striped pattern and experienced greater pattern glare. They were also more likely to select a colored filter to aid visual comfort, particularly colors in the blue-to-green sector of the spectrum. Color vision was impaired subtly but significantly in migraine. Principal component analyses grouped common headache triggers into 5 broadly equal components: food, visual triggers, alcohol, stress and tiredness, and the environment. In a second analysis, the overall number of illusions seen in striped patterns was associated with visual triggers while pattern glare, use of colored filters, and interictal light sensitivity together formed a sixth component interpreted as visual stress.

Conclusions: It is suggested that clinicians should ask migraine patients whether visual stimuli trigger their migraine, about interictal visual symptoms, and use the pattern glare test to ensure that those who may benefit from optometric interventions are appropriately managed.