Objective: To observe the interocular symmetry of foveal threshold (FT) and optical coherence tomography
angiography (OCTA) parameters in healthy middle-aged and elderly subjects. Methods: Cross-sectional
observational study. Sixty-six eyes from thirty-three subjects were enrolled to compare binocular ocular perfusion pressure (OPP), FT, non-flow area (NFA), superior vessel density (SVD) and deep vessel density (DVD) in a
3 mm × 3 mm OCTA scan of macula. The interocular symmetry of all the parameters was analyzed; the
correlations of the differences (△), mean value (m) and the ratio of all the parameters with age and gender were
analyzed. Results: There was no significant interocular difference revealed by paired-samples t-tests in all the
parameters (P>0.05) except FT (t=?2.118, P=0.042), while the rank of Pearson’s correlation index and intraclass
correlation coefffcient (ICC) from strong to weak was OPP > FT > NFA > DVD > SVD. The interocular
symmetry of all the parameters was proved to be good with Bland-Altman plots, and it changed little with the
variations of age and gender. Conclusion: Interocular symmetries of FT and OCTA parameters are observed in
healthy middle-aged and elderly subjects.