Glaucoma Diagnosis of the Optic Nerve Head Using Optical Coherence Tomography - Significance of Bruch's Membrane Opening and Derived OCT Parameters.

Background: With the introduction of optical coherence tomography (OCT) in glaucoma imaging, the neuroretinal tissue of the retina and optic nerve head can be measured and quantified at different measuring points, much more accurately than with previous imaging techniques. In addition to macular parameters such as the macular and peripapillary thickness of the retinal nerve fibre thickness and the macular ganglion cell layer thickness, parameters close to the papillary were also defined, as based on the Bruch's membrane opening (BMO), and examined with regard to their suitability for glaucoma diagnostics. This overview presents the advantages and disadvantages of these parameters in glaucoma diagnostics.

Materials and methods: Review of current literature in PubMed as well as synopsis of relevant guidelines.

Results and conclusion: The minimum marginal width of the Bruch's membrane opening (BMO-MRW) is the most frequently used OCT parameter for measuring the neuroretinal marginal width of the optic nerve head. There are also area parameters. Compared to peripapillary RNFL thickness and macular parameters, BMO-MRW has equivalent to superior sensitivity in glaucoma detection. In the longitudinal view, effects such as changes in the eye pressure level lead to fluctuations in BMO-MRW, which limits the usefulness of this parameter with regard to morphometric progression analysis. Numerous studies have shown that peripapillary nerve fibre layer thickness (pRNFL) is better suited for progression analysis. Checking the automatic segmentation of OCT images is relevant for all OCT parameters in glaucoma diagnostics.