Quantitative analysis of macular and optic disc microvascular parameters in patients with immunoglobulin A nephropathy using optical coherence tomography angiography.

Background: Immunoglobulin A nephropathy (IgAN) is a common chronic glomerulonephritis. The kidneys and eyes have structural and developmental similarities, but ocular microvascular changes in IgAN, especially in the macular and optic disc, are poorly studied. This study aimed to assess these microvascular parameters in IgAN patients using optical coherence tomography (OCT) and OCT angiography (OCTA) and explore their associations with clinical data.

Methods: This is a case-control study. Fifteen patients with IgAN and 15 healthy controls (HCs) who attended The Affiliated Hospital of Southwest Medical University between July 2022 and December 2023 were selected. OCT and OCTA were used to assess macular thickness, retinal nerve fiber layer (RNFL) thickness, the vascular density (VD) and perfusion density (PD) of macular and optic disc, and foveal avascular zone (FAZ). In addition, we analyzed the association between OCT and OCTA parameters and clinical data in patients with IgAN.

Results: VD and PD were significantly lower in the macular area in the IgAN group than the HCs (VD: 18.270±0.683 vs. 18.943±0.357, P<0.001; PD: 0.447±0.019 vs. 0.464±0.009, P<0.001). VD and PD in the macular area were negatively correlated with urine protein levels (VD: ρ=-0.604, P=0.017; PD: ρ=-0.551, P=0.033) and urine microalbumin levels (VD: ρ=-0.762, P=0.001; PD: ρ=-0.751, P=0.001). The FAZ area was positively correlated with 24-h urine volume (ρ=0.651, P=0.009).

Conclusions: Compared with HCs, the status of macular microcirculation in the IgAN group was significantly decreased, and some microvascular parameters were significantly correlated with the clinical data.