Mechano-Vascular Considerations in Duane Syndrome: An OCTA Study of Macular Perfusion.

PURPOSE: To compare macular vessel density (VD) between Duane syndrome (DS) patients and healthy controls using optical coherence tomography angiography (OCTA). METHODS: In this prospective study, age- and sex-matched DS patients and healthy controls underwent OCTA using a Topcon DRI OCT-1 Triton device. VD was measured in the superficial capillary plexus (SCP), deep capillary plexus (DCP), outer retina (OR), and choriocapillaris (CC) across five macular quadrants (central, nasal, temporal, superior, inferior). The Benjamini-Hochberg procedure was applied to control the false discovery rate (FDR) across 20 primary comparisons. Generalized estimating equations accounted for inter-eye correlations. RESULTS: The study included 114 eyes from 64 participants (29 DS patients, 43 eyes; 35 control subjects, 71 eyes). Groups were comparable in age, sex, axial length, and other baseline characteristics (all p > 0.05). Before correction, DS patients showed nominally higher central SCP VD (22.55 ± 5.9% vs. 21.8 ± 5.2%, p = 0.031) and nominally lower VD in the DCP inferior quadrant (45.81 ± 5.7% vs. 48.19 ± 2.6%, p = 0.011), CC temporal quadrant (53.32 ± 2.6% vs. 54.21 ± 1.9%, p = 0.037), and CC superior quadrant (51.09 ± 3.5% vs. 52.7 ± 2.5%, p = 0.010). After Benjamini-Hochberg FDR correction, none of these differences retained statistical significance (all q > 0.05). No differences were observed in the OR (all p > 0.05). CONCLUSION: In this clinical study, no statistically significant macular vascular differences were identified between DS patients and healthy controls after rigorous correction for multiple comparisons. However, observed trends toward central SCP hyperperfusion and regional DCP and CC hypoperfusion generate hypotheses regarding potential mechano-vascular effects of chronic extraocular muscle co-contraction in DS. These findings warrant confirmation in larger prospective cohorts with pre-specified primary outcomes.