Multifractal and lacunarity features of retinal microvasculature in migraine: an optical coherence tomography angiography study.

Purpose: To determine the multifractal and lacunarity characteristics of the retinal microvasculature in patients with migraine and compare with healthy controls.

Methods: A total of 177 eyes from 56 migraine patients (35 without aura, 21 with aura) and 102 eyes from 51 healthy controls were included. Optical coherence tomography angiography (OCTA) was used to assess foveal and parafoveal vascular parameters. Vascular area density, vascular length density, vascular diameter index, vascular tortuosity, branch point density, non-flow area, and foveal avascular zone parameters were measured with ImageJ. Fractal dimensions (D₀, D₁, D₂), multifractal spectrum (D(q)), and lacunarity (parameter b) were calculated using MATLAB.

Results: Migraine with aura patients showed significantly reduced vascular area density, vascular length density, vascular diameter index, and branch point density values, particularly in the deep capillary plexus. The foveal avascular zone area and perimeter were significantly enlarged in the migraine with aura group. Fractal analysis revealed a significant decrease in D₀, D₁, and D₂ values in migraine with aura, especially in the deep capillary plexus. The multifractal spectrum (D(q)) exhibited a consistent downward shift in migraine with aura, suggesting global architectural simplification. Although not statistically significant, lacunarity analysis showed a trend toward increased spatial heterogeneity in migraine with aura, reflected by lower b values.

Conclusion: Migraine, particularly with aura, is associated with reduced vascular complexity and increased spatial irregularity in the retinal microvasculature, especially at the level of the deep capillary plexus. Multifractal and lacunarity metrics may serve as sensitive indicators of subclinical microvascular disruption in migraine.