Migraine-type photophobia, most commonly described as exacerbation of headache by light, affects nearly 90% of the patients. It is the most bothersome symptom accompanying an attack. Using subjective psychophysical assessments, we showed that migraine patients are more sensitive to all colors of light during ictal than during interictal phase and that control subjects do not experience pain when exposed to different colors of light. Based on these findings, we suggested that color preference is unique to migraineurs (as it was not found in control subjects) rather than migraine phase (as it was found in both phases). To identify the origin of this photophobia in migraineurs, we compared the electrical waveforms that were generated in the retina and visual cortex of 46 interictal migraineurs to those generated in 42 healthy controls using color-based electroretinography and visual-evoked potential paradigms. Unexpectedly, it was the amplitude of the retinal rod-driven b wave, which was consistently larger (by 14%-19% in the light-adapted and 18%-34% in the dark-adapted flash ERG) in the migraineurs than in the controls, rather than the retinal cone-driven a wave or the visual-evoked potentials that differs most strikingly between the 2 groups. Mechanistically, these findings suggest that the inherent hypersensitivity to light among migraine patients may originate in the retinal rods rather than retinal cones or the visual cortex. Clinically, the findings may explain why migraineurs complain that the light is too bright even when it is dim to the extent that nonmigraineurs feel as if they are in a cave.
Affected by the disease, the eyes of migraine patients are more sensitive to light than the eyes of nonmigraine subjects.
aHarvard Medical School, Boston, MA, United States
bDepartment of Neurology, Brigham and Women's Faulkner Hospital, Boston, MA, United States
cDepartment of Anesthesia, Critical Care and Pain Medicine, Beth Israel Deaconess Medical Center, Boston, MA, United States
dDepartment of Ophthalmology, Children's Hospital Boston, Boston, MA, United States
eHarvard Catalyst Clinical Research Center, Beth Israel Deaconess Medical Center, Boston, MA, United States
fDepartment of Medicine, Beth Israel Deaconess Medical Center, Boston, MA, United States
gDepartment of Neurology, Beth Israel Deaconess Medical Center, Boston, MA, United States
hDepartment of Medicine, Mount Auburn Hospital, Cambridge, MA, United States
iDepartment of Anesthesia, Critical Care and Pain Medicine, Center for Pain and the Brain, Boston Children's Hospital, Boston, MA, United States
Corresponding author. Address: Department of Anesthesia, Critical Care and Pain Medicine, Beth Israel Deaconess Medical Center, CLS-649, 3 Blackfan Circle, Boston, MA 02215, United States. Tel.: 617 735-2832; fax: 617 735-2833. E-mail address: email@example.com (R. Burstein).
Sponsorships or competing interests that may be relevant to content are disclosed at the end of this article.
Received July 30, 2018
Accepted September 20, 2018