Layer-specific retinal microvascular redistribution in children with severe adenotonsillar hypertrophy assessed by optical coherence tomography angiography

This study aims to compare the parafoveal retinal microcirculation in children with severe adenotonsillar hypertrophy (ATH) and healthy controls using optical coherence tomography angiography (OCTA). Sixty-six eyes (31 children with ATH and 35 healthy controls) were analyzed. Parafoveal OCTA images (6 × 6 mm) were obtained using a swept-source OCTA device (DRI OCT Triton; Topcon Corporation, Tokyo, Japan). Vessel density (VD) of the superficial capillary plexus (SCP) and deep capillary plexus (DCP) was measured in the central and four parafoveal quadrants. The foveal avascular zone (FAZ) area was also measured in both plexuses. DCP vessel density was significantly higher in the ATH group than control group in the temporal [59.29 ± 3.22% vs. 47.16 ± 5.87%], superior [57.77 (56.21–58.77)% vs. 49.15 ( 44.66–52.13)%], nasal [58.12 ( 55.36–59.44)% vs. 48.98 ( 46.38–50.04)%], and inferior [56.89 (54.56–58.05)% vs. 44.87 (41.85–47.84)%] quadrants (all BH-FDR adjusted p < 0.001). The superficial FAZ area was smaller in the ATH group (0.311 ± 0.089 mm² vs. 0.358 ± 0.096 mm²; unadjusted p = 0.043), although this difference did not remain significant after Benjamini–Hochberg false-discovery-rate correction (BH-FDR adjusted p = 0.103). No significant differences were observed in deep FAZ area, SCP vessel density across all quadrants, or DCP central vessel density between the groups (all BH-FDR adjusted p > 0.05). Severe adenotonsillar hypertrophy is associated with layer-specific retinal microvascular alterations on OCTA. Deep capillary plexus vessel density was significantly increased in parafoveal regions, suggesting non-uniform microvascular involvement driven by differences in metabolic demand and autoregulatory mechanisms between retinal layers.