Localising OCTA changes induced by the isometric hand-grip test to the superficial retina in neovascular age-related macular degeneration

Purpose This study uses optical coherence tomography angiography (OCTA) topographical cluster analysis to localise where vascular changes occur during the isometric hand-grip test (IHGT) in eyes with neovascular age-related macular degeneration (AMD). Methods This prospective study included single eyes from 44 participants with neovascular AMD. Systemic blood pressure (BP) and macular 6 × 6 mm OCTA scans were obtained before the IHGT, during the IHGT, and after the IHGT. The main outcome was the change in processed OCTA signal (%), measured within high-density (126 × 126) grids and analysed by topographical clusters across the superficial retina, deep retina, and choriocapillaris. Results were compared against test–retest thresholds to differentiate true IHGT-induced changes from measurement variability. Results The IHGT increased systolic (13.83 [3.28, 24.39] mmHg) and diastolic BP (7.04 [3.57, 10.52] mmHg; P < 0.01). Adjusted for test–retest thresholds, the IHGT increased processed OCTA signal (12.84 [8.49, 26.77] %, P < 0.0001) at nasal clusters in the superficial retina. These changes were moderately correlated with systolic BP increases (Spearman r = 0.43, P < 0.05), but not with diastolic BP. No changes were observed in the deep retina or choriocapillaris. Systemic BP and processed OCTA signal returned to baseline within 30 s after IHGT release. Conclusion Hand-squeezing temporarily increases processed OCTA signal in the nasal superficial retina. This response may serve as a valuable marker of vascular function. Consequently, caution is warranted when interpreting OCTA following BP changes, such as those induced by physical activity or medication changes.