Interocular symmetry of retinal and choroidal OCT parameters in precapillary pulmonary hypertension: a brief research report.

Purpose: To assess interocular symmetry of retinal and choroidal optical coherence tomography (OCT)-derived parameters in patients with precapillary pulmonary hypertension (PH) and healthy controls, and to evaluate the implications of symmetry for oculomics-based biomarker development. Methods: In this cross-sectional study, 29 patients with precapillary PH and 37 age- and sex-matched healthy controls underwent standardized spectral-domain OCT. Retinal and choroidal thicknesses, volumes and binarized choroidal biomarkers were quantified using validated protocols. Interocular agreement was assessed with intraclass correlation coefficients (ICC), Spearman's rank correlation ( Results: Median interocular agreement was good but parameter-specific (ICC 0.76 in precapillary PH and 0.78 in controls). In PH, agreement was highest for choroidal metrics. In controls, it was lowest for retinal pigment epithelium thickness. No systematic laterality bias was detected in PH, whereas two parameters remained significant in controls. Absolute inter-eye differences were small but greater in PH for selected temporal and nasal retinal thickness and volume subfields. Conclusions: Interocular agreement was parameter-specific in both groups. In precapillary PH, one-eye sampling appears most defensible for choroidal biomarkers. Selected retinal parameters showed poor agreement, or greater absolute differences in precapillary PH than in controls, and require individual validation.