Purpose: To compare retinal nerve fiber layer thickness (RNFLT) and Bruch's membrane opening minimum rim width (BMO-MRW) measured by spectral domain optical coherence tomography (SDOCT) for diagnosing glaucoma in those suspected of having the disease.
Design: Observational cohort study.
Participants: 113 eyes from 81 patients suspected of having glaucoma based on optic nerve appearance.
Methods: Participants were imaged using SDOCT and RNFLT and BMO-MRW were measured. All participants had normal visual fields at the time of imaging, but were considered suspects based on the appearance of the optic disc during clinical examination. Eyes were classified as glaucomatous or non-glaucomatous based on documented stereophotographic evidence of progressive glaucomatous change in the appearance of the optic nerve or retinal nerve fiber layer occurring before the imaging session. For each parameter, we calculated the area under the receiver operating characteristic (ROC) curve and the sensitivity with fixed specificities of 80% and 95%.
Main outcome measures: Areas under the ROC curves.
Results: Of the 113 eyes suspected of having glaucoma, 52 (46.0%) eyes had progressive glaucomatous optic nerve changes and were classified as having pre-perimetric glaucoma and 61 (54.0%) eyes did not have progressive glaucomatous optic nerve changes (followed untreated for an average of 9.4±3.2 years) and were classified as normal. The areas under the ROC curves were 0.89 (95% CI: 0.84-0.95) for global RNFLT and 0.75 (95% CI: 0.65-0.85) for global BMO-MRW (p=0.006). The sensitivity at 95% specificity was 60% for the global RNFLT parameter and 40% for the global BMO-MRW parameter. The RNFLT parameters that achieved areas under ROC curve ≥0.80 were global (0.89), supero-temporal (0.80), infero-temporal (0.87), and supero-nasal (0.81). The only BMOBRW parameter that achieved area under ROC curve ≥0.80 was infero-temporal (0.82).
Conclusions: Our findings suggest that RNFLT parameters may be better able to identify pre-perimetric glaucomatous damage in glaucoma suspects than BMO-MRW.