To characterize and quantify Bruch membrane opening (BMO)-based optic nerve head (ONH) parameters in a large, young and healthy, predominantly white population.

Cross-sectional study and reliability analysis.

The ONH of 1344 predominantly white subjects were imaged with spectral-domain optical coherence tomography (SD-OCT). A customized script, coded in Matlab, was used to manually segment and measure multiple BMO-based parameters of the ONH. Measurements were compared to those obtained with confocal scanning laser ophthalmoscopy (Heidelberg Retina Tomograph; HRT). Regression analysis was performed to assess the relationship between BMO parameters and other ocular and demographic variables.

Mean BMO disc and neuroretinal rim (NRR) areas ranged from 0.94 to 4.06 mm² (mean 1.77 ± 0.38 mm²) and 0.94 to 3.99 mm² (mean 1.56 ± 0.31 mm²), respectively. When compared to the equivalent HRT measurements, SD-OCT-derived measures differed significantly for all comparable ONH parameters (P < .001). The limits of agreement computed from Bland-Altman plots comparing SD-OCT and HRT measurements showed suboptimal agreement between the techniques. Linear regression analysis demonstrated an effect of ethnicity, axial length, and refractive error on BMO-based parameters.

We have quantified BMO-based parameters in a large cohort of young adults using SD-OCT. These data will be informative in constructing normative profiles for clinical and research purposes in glaucoma diagnosis and management.