Choroidal vascularity index and retinal microvascular alterations in hidradenitis suppurativa

Hidradenitis suppurativa (HS) is increasingly recognized as a systemic inflammatory disease, yet its potential effects on retinal and choroidal microvasculature remain poorly understood. We investigated OCT- and OCTA-derived retinal, choroidal, and macular findings in patients with HS and assessed their relationships with disease severity and laboratory parameters. This retrospective study included 31 patients with HS (treatment-naïve) and 29 age- and sex-matched healthy controls. Best-corrected visual acuity, intraocular pressure, body mass index, disease severity scores (Hurley stage and International Hidradenitis Suppurativa Severity Score System [IHS4]), blood laboratory parameters, OCTA metrics, choroidal vascularity index (CVI), choroidal thickness, and macular thickness parameters were analyzed. Among ocular parameters, superficial capillary plexus average vessel density was significantly higher in the HS group than in controls (47.1 ± 3.71% vs. 42.7 ± 9.91%, p = 0.028), while CVI was significantly lower in HS eyes (61 ± 4% vs. 68 ± 4%, p < 0.001). Other OCTA, choroidal thickness, and macular thickness parameters did not differ significantly between groups. Within the HS group, CRP levels showed a moderate negative correlation with CVI values ( r = − 0.422, p = 0.001). ROC analysis demonstrated good discriminatory performance of CVI for differentiating HS patients from healthy controls (AUC = 0.869, 95% CI: 0.801–0.937, p < 0.001). HS was associated with reduced CVI and altered superficial retinal microvascular density, providing preliminary evidence of possible retinal and choroidal microvascular alterations. The clinical significance of these findings remains uncertain and requires confirmation in longitudinal studies.