Sex-Related Differences in Ocular Blood Flow of Healthy Subjects Using Laser Speckle Flowgraphy

To evaluate sex-related differences in ocular blood flow of healthy subjects using laser speckle flowgraphy (LSFG). In this prospective cross-sectional study, we examined 103 healthy volunteers (47 males, 56 females; mean age: 39.3 ± 15.6 years and 42.1 ± 18.7 years, respectively). The blood flow to the optic nerve head (ONH) and choroid was assessed with LSFG, including mean blur rate (MBR) and pulse waveform variables. We evaluated sex-related differences in these variables and compared them with those in other clinical parameters. A linear single regression showed that the ONH-MBR (r = -0.402, P < 0.001) and five ONH pulse waveforms were significantly correlated with sex. A multiple stepwise regression analysis revealed that sex (β = 0.389, P < 0.001) and age (β = -0.290, P = 0.002) were independent factors, indicating the ONH-MBR, age (β = -0.394, P < 0.001), and subfoveal choroidal thickness (β = 0.221, P = 0.016) were independent factors indicating the choroidal MBR. Moreover, sex was an independent factor indicating the five ONH pulse waveform parameters that were consistent with results of the linear single regression. The optic nerve head MBR in the female group was significantly higher than that in the male group (P < 0.001), but no differences were observed in the choroid between the groups (P > 0.05). Sex-related differences are present in ocular blood flow in the ONH, but not in the choroid in healthy subjects. We believe that these differences should be considered when interpreting blood flow data in ocular diseases.