Spectral-Domain Optical Coherence Tomography-Derived Characteristics of Bruch Membrane Opening in a Young Adult Australian Population

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

DESIGN: Cross-sectional study and reliability analysis.

METHODS: 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.

RESULTS: 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.

CONCLUSIONS: 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.