Bruch's membrane opening minimum rim width and retinal nerve fiber layer thickness in a Brazilian population of healthy subjects.

Camila S Zangalli,Claude F Burgoyne,Balwantray C Chauhan,Jamil Miguel-Neto,Jayme R Vianna,Vital P Costa,Alexandre S C Reis,Sanjoy Bhattacharya

doi:10.1371/journal.pone.0206887

Abstract

ObjectiveTo determine Bruch’s membrane opening (BMO) minimum rim width (MRW) and peripapillary retinal nerve fiber layer thickness (RNFLT) measurements, acquired with optical coherence tomography (OCT) in healthy Brazilian individuals self-reported as African Descent (AD), European Descent (ED) and Mixed Descent (MD).Methods260 healthy individuals (78 AD, 103 ED and 79 MD) were included in this cross-sectional study conducted at the Clinics Hospital of the University of Campinas. We obtained optic nerve head (24 radial B scans) and peripapillary retinal nerve fiber layer (3.5-mm circle scan) images in one randomly selected eye of each subject.ResultsAfter adjustment for BMO area and age, there were no significant differences in mean global MRW (P = 0.63) or RNFLT (P = 0.07) among the three groups. Regionally, there were no significant differences in either MRW or RNFLT in most sectors, except in the superonasal sector, in which both MRW and RNFLT were thinner among ED (P = 0.04, P<0.001, respectively). RNFLT was also thinner in ED in the inferonasal sector (P = 0.009). In all races, global MRW decreased and global RNFLT increased with BMO area. AD subjects had higher rates of global RNFLT decay with age (-0.32 μm/year) compared to ED and MD subjects (-0.10 μm/year and -0.08 μm/year, respectively; P = 0.01 and P = 0.02, respectively).Conclusions and relevanceWhile we found no significant differences in global MRW and RNFLT among the three races, age-related thinning of the RNFLT was significantly higher in the AD subgroup, which warrants further study.

Highlights

Assessment of the optic nerve head (ONH) is vital for the detection and follow-up of glaucoma damage
After adjustment for Bruch’s membrane opening (BMO) area and age, there were no significant differences in mean global Minimum Rim Width (MRW) (P = 0.63) or retinal nerve fiber layer thickness (RNFLT) (P = 0.07) among the three groups
Global MRW decreased and global RNFLT increased with BMO area

Summary

Introduction

Assessment of the optic nerve head (ONH) is vital for the detection and follow-up of glaucoma damage. OCT BMO Minimum Rim Width (MRW) is a parameter that uses BMO as the anatomic reference point and MRW is defined as the shortest distance between BMO and the internal limiting membrane, in effect, measuring the neuroretinal rim perpendicular to the trajectory of the overlying rim tissue [9, 10]. It takes into account the orientation of the RGC axons as they pass through BMO to enter the anterior neural canal. MRW measurements have demonstrated better diagnostic performance for detecting glaucoma than other rim parameters [11] and better structure-function relationships [12] with visual field testing

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