Retinal superficial microvascular impairment in migraine: a swept-source OCTA study of disease severity and chronicity

Migraine is increasingly recognized as a disorder involving neurovascular dysfunction, but the characteristics and clinical relevance of retinal microvascular alterations across migraine phenotypes remain incompletely understood. Swept-source optical coherence tomography angiography (SS-OCTA) enables non-invasive assessment of retinal vascular changes across distinct vascular plexuses. This study investigated retinal microvascular alterations in migraine and their associations with migraine chronicity and clinical disease burden. This cross-sectional observational study with prospective recruitment included 173 patients with migraine and 69 healthy controls. Patients with migraine were classified as having episodic migraine (EM, n = 136) or chronic migraine (CM, n = 37) according to ICHD-3. SS-OCTA was performed during the interictal headache-free period. Vascular density of the superficial vascular complex (SVC), deep vascular complex (DVC), and choriocapillaris (CC) was quantified. Generalized estimating equation models were used to account for inter-eye correlations and assess associations between OCTA parameters and clinical measures after adjustment for relevant covariates. Compared with healthy controls, patients with migraine had significantly lower SVC density (45.22 ± 1.61% vs. 45.65 ± 1.16%; P = 0.015), whereas DVC and CC measures did not differ significantly between groups. SVC density was further reduced in patients with CM compared with those with EM, suggesting an association between superficial retinal microvascular alteration and migraine chronicity. Among patients with migraine, lower SVC density was associated with greater attack frequency (β = −0.220, P = 0.030), higher pain intensity (β = −0.200, P = 0.025), and greater migraine-related disability (β = −0.200, P = 0.045). These secondary associations should be interpreted as exploratory given the number of statistical comparisons. Migraine was associated with selective reduction of SVC density, with more pronounced impairment in chronic migraine and associations with measures of migraine burden. The layer-specific findings suggest that retinal microvascular alterations in migraine may not be uniform across vascular plexuses and may reflect differences in neurovascular regulation. SVC density may therefore represent a candidate imaging marker associated with migraine burden.