Fig. 1

Correlation between PM2.5 and limbal epithelium thickness in humans. (A) FD-OCT images of people from regions with a distinct annual average concentration of PM2.5 were collected and limbal epithelium thickness was measured using IPP6.0. The limbal epithelium scale was identified according to its anatomical marks. Shaded areas indicated the target limbal epithelium. AM, anterior margin of limbus; PM, posterior margin of limbus; SS, scleral spur; BM, Bowman’s membrane; DM, Descemet’ s membrane. (B) The 5-year average concentration of PM2.5 in people from different regions in Zhejiang Province. Every plot indicated an annual average concentration of PM2.5 (2018–2022). Data were publicly released by the Ecological Environment Department of Zhejiang. (C) FD-OCT image of the limbus in two groups (scale bar, 250 μm). White arrowhead indicated limbal epithelium. (D) Violin plot diagram of mean/maximum/minimum value in two groups (*p < 0.05, **p < 0.01). (E) Spearman analysis was conducted to separately define the correlation between PM2.5 concentration and mean/maximum/minimum value of limbal epithelium thickness. The red line indicates the fitted regression line. FD-OCT: Fourier-domain Optical Coherence Tomography