Evaluation of retinal microvascular structures by optical coherence tomography angiography in primary Sjögren’s syndrome

Objectives There are insufficient data in the literature on how retinal capillaries are affected in primary Sjögren's syndrome (PSS). The aim of this study was to evaluate the retinal capillary density (CD) in PSS using optical coherence tomography angiography (OCTA). Methods In this case–control study, 26 eyes from 13 PSS patients and 39 eyes from 20 healthy controls (HCs) were included. The CD in the regions of the superior capillary plexus (SCP), deep capillary plexus (DCP) and radial peripapillary capillaries (RPC) as well as assessment parameters of the foveal avascular zone (FAZ) were examined by OCTA. Results The mean CD (%) was 50.2 ± 4.2 and 50.5 ± 3.4 in the SCP ( p = 0.904), 49.2 ± 7.5 and 53.9 ± 5.7 in the DCP ( p = 0.006) and 50.8 ± 2.1 and 49.8 ± 2.2 in the RPC ( p = 0.088) regions in patients with PSS and HCs, respectively. In patients with PSS and HCs, the mean sizes of the FAZ were 0.243 ± 0.07 mm 2 and 0.283 ± 0.13 mm 2 ( p = 0.142), and the mean sizes of the non-flow area were 0.480 ± 0.11 mm 2 and 0.509 ± 0.13 mm 2 , respectively ( p = 0.359). The correlation coefficients (Rho) of retinal CD in the SCP, DCP and RPC regions with disease duration were − 0.545 ( p = 0.004), − 0.389 ( p = 0.050) and − 0.795 ( p < 0.001), respectively. Conclusion The retinal CD in PSS is lower than that in the healthy population in deep retinal capillaries, and retinal CD shows a negative correlation with disease duration in PSS. Clinical trials registration This study was not registered to clinicaltrials.gov.