Patients with migraine and headache disorders who also have photophobia may have greater interictal light sensitivity compared with those without photophobia and healthy individuals, according to a study published in Headache.
Cortical hypersensitivity resulting from reduced tolerance to headache triggers and persistent avoidance is thought to mediate associations between headache-related symptoms and visual factors.
A total of 491 university students (83.7% women; mean age, 26.29) reporting ≥1 headache annually were recruited between June and August 2015 to participate in an online survey on visual symptoms of headache, interictal light sensitivity and visual triggers of headache. Using the Brief Headache Screen, the Headache Triggers Sensitivity and Avoidance Questionnaire, and the Visual Aura Rating Scale, participants were categorized as having headache disorder with photophobia (group A1), having headache disorder without photophobia (A2), not having any disorder (control group, A3), and having headache disorder with visual aura (B1), headache disorder without visual aura (B2), or no disorder (B3).
Regarding photophobia and interictal light sensitivity, there were significant differences between the A groups (photophobia; P < .001), with participants in the A1 group indicating higher interictal light sensitivity compared with those in the A2 and A3 groups (P <.001 for both). A similar pattern was found for flicker (P <.001) and glare (P <.001) visual triggers, with a higher frequency of both phenomena reported by participants in the A1 vs A2 or A3 groups (P ≤.001 for all). This was not the case for eyestrain as a trigger in the photophobia groups, despite a significant between-group difference (P <.001).
In terms of the presence or absence of visual aura and interictal light sensitivity, although there were significant between-group differences between the 3 B groups (P =.001), pairwise comparisons did not reveal significant differences between B1 and B2 (P =.834), but indicated differences between B1 and B3 (P =.008). The frequency of flicker, glare, and eyestrain as headache triggers were found to be different between the 3 groups (P =.001; P <.001; and P =.001, respectively). No significant difference between B1 and B2 for flicker (P =.073), glare (P =.731), or eyestrain (P =.996) were found, but significant differences between B1 and B3 were found for flicker (P =.001), glare (P <.001) and eyestrain (P =.018).
A significant association between visual aura and photophobia was found in participants with headache disorder (P <.001).
Study limitations include a lack of information on recruiting source, the use of subjective self-reports, possible recall bias, and a lack of clarity regarding the correlation between study effect sizes and actual functional differences.
“This study supports a link between certain visual phenomena in headache disorder populations, and supports future research into exposure-based treatments for migraine symptoms,” noted the authors.
Hayne DP, Martin PR. Relating photophobia, visual aura, and visual triggers of headache and migraine. Headache. 2019;59(3):430-442. doi: 10.1111/head.13486