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

PurposeTo 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.MethodsIn a case-control, cross-sectional study, 125 eyes of 125 patients with disc size >2.45 mm2, 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.ResultsAll participants had a mean disc area of 2.91±0.38 mm2 in CSLT and a BMO area of 2.45±0.39 mm2 (r=0.76;P<0.001). In glaucoma patients, visual field mean deviation was -10.0±6.1 dB. Global BMO-MRW correlated better to visual field function (Spearman's Rho (ρ)=0.71; P<0.001) than RNFLT (ρ=0.52;P<0.001) and CSLT rim area (ρ=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.ConclusionsIn 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.