Bruch's membrane opening-based optical coherence tomography of the optic nerve head: a useful diagnostic tool to detect glaucoma in macrodiscs

Purpose To compare Bruch's membrane opening (BMO)-based spectral domain optical coherence tomography (SD-OCT) and margin based confocal scanning laser tomography (CSLT) of the optic nerve head (ONH) to visual field function in large optic discs (macrodiscs) and to assess performance for glaucoma detection. Methods In a case-control, cross-sectional study, 125 eyes of 125 patients with disc size > 2.45 mm(2), thereof 44 glaucoma and 11 ocular hypertension (OHT) patients and 70 healthy controls underwent SD-OCT and CSLT examination, visual field testing and clinical evaluation. Mean outcome measures BMO-based minimum rim width (BMO-MRW), retinal nerve fiber layer thickness (RNFLT) in SD-OCT, and rim area measured in CSLT were compared and correlated to visual field function. Results All participants had a mean disc area of 2.91 +/- 0.38 mm(2) in CSLT and a BMO area of 2.45 +/- 0.39 mm(2) (r = 0.76; < 0.001). In glaucoma patients, visual field mean deviation was -10.0 +/- 6.1 dB. Global BMOMRW correlated better to visual field function (Spearman's Rho (rho) = 0.71;P < 0.001) than RNFLT (rho = 0.52; P < 0.001) and CSLT rim area (rho = 0.63;P < 0.001). BMO-MRW was significantly decreased with higher visual field loss (P < 0.001). In ROC analysis, diagnostic power to differentiate glaucoma patients and healthy controls was highest for BMO-MRW (Area under curve, AUC = 0.96; sensitivity at 95% specificity = 82%). Rim area in CSLT (AUC = 0.91; sensitivity = 61.0%; P = 0.04) and RNFLT (AUC = 0.89; sensitivity = 61%; P = 0.01) were significantly less powerful. Conclusions In macrodiscs, BMO-MRW has the best diagnostic power to discriminate glaucoma patients from normal controls compared to RNFLT and rim area in CSLT. Additionally, BMO-MRW seems to reflect the structure-function relationship better than the other two parameters.