Targeting the intrinsically photosensitive retinal ganglion cell to reduce headache pain and light sensitivity in migraine: A randomized double-blind trial

Approximately 80% of patients with migraine report light sensitivity during attacks and almost half report that following headache, light sensitivity is the most bothersome symptom. Light wavelengths stimulating intrinsically photosensitive retinal ganglion cells (IPRGCs) exacerbate headache-associated light sensitivity; green light is most comfortable. We developed optical tints that block wavelengths exacerbating migraine pain and transmit wavelengths that are most comfortable. We studied patients with migraine to determine if spectacles with these tints ameliorate headache pain and light sensitivity. Randomized participants wore control lenses or lenses blocking light wavelengths that stimulate IPRGCs. Participants applied the lenses at migraine onset and recorded baseline, two- and four-hour headache pain on an 11-point scale. Primary endpoint was pain reduction at two hours following the first severe or very severe headache. Statistical tests used included mixed-effects model analysis, Mann-Whitney test, Cochran-Mantel-Haenszel test, Shapiro-Wilk test, Welch t-test. In 78 subjects, two- and four-hour pain reduction was not significantly different between groups. In post-hoc analyses of headaches with baseline pain scores ≥ 2, a mixed-effects model suggested that IPRGC lenses were associated with clinically and statistically significant reductions in two- and four-hour headache pain. In post-hoc analyses, fewer subjects wearing IPRGC lenses reported two-hour light sensitivity. Preliminary evidence suggests that optical tints engineered to reduce stimulation of IPRGCs may reduce migraine-associated pain and light sensitivity. Trial Registration: This study was registered at ClinicalTrials.gov (NCT04341298).