Diagnostic Classification of Bruch's Membrane Opening-Minimum Rim Width and Retinal Nerve Fiber Layer Thickness in Myopic Eyes by Optical Coherence Tomography.

Mingzhi Zhang,Geng Wang,Ji Wang,Cui Liu,Kunliang Qiu,Shasha Liu,Miaoru Zhen

doi:10.3389/fmed.2021.729523

Abstract

Purpose: This study was conducted in order to compare the diagnostic classification of Bruch's membrane opening-minimum rim width (BMO-MRW) and RNFL thickness in normal myopic subjects by using optical coherence tomography (OCT).Methods: This cross-sectional study involved 75 healthy myopic subjects [spherical equivalent (SE) ≤ −0.5D] from April 2019 to January 2020. One eye of each subject was randomly selected for examination. BMO-MRW and peripapillary RNFL thickness were measured by spectral-domain OCT (Spectralis, Heidelberg Engineering GmbH, Heidelberg, Germany). All the subjects were divided into three groups: low myopic group (SE > −3D), moderate myopic group (−6D < SE ≤ −3D), and high myopic group (SE ≤ −6D). A nonparametric test was used to analyze the difference among groups. Linear regression was used to analyze the relationship between BMO-MRW/RNFL thickness and axial length/spherical equivalent. McNemar test was used to compare the diagnostic classification between BMO-MRW and RNFL thickness.Results: The RNFL thickness classified a significantly higher percentage of eyes as outside normal limits/borderline in at least 1 quadrant (BMO-MRW, 4%; RNFL thickness, 34.67%; p < 0.01). There was no significant correlation between BMO-MRW/RNFL thickness and AL/SE. The low myopia (SE > −3D) had a significantly lower percentage of eyes classified as outside normal limits/borderline in at least 1 quadrant than the moderate myopia (−6D < SE ≤ −3D) and high myopia (SE ≤ −6D) (low myopia, 12.5%; moderate/high myopia, 42.42%/50%; p < 0.05).Conclusion: BMO-MRW had a lower percentage of eyes classified as outside normal limits/borderline in at least 1 quadrant than RNFL thickness in normal myopic subjects. When referring to the diagnostic classification of RNFL thickness in myopic subjects, caution should be exercised in interpreting positive results. Further studies are needed to compare the diagnostic accuracy of these two measurements in myopic glaucoma patients.

Highlights

Myopia is a common ocular disorder worldwide
There was no significant correlation between BMO-MRW and axial length (AL)/spherical equivalent (SE)
This study found that there was no significant correlation between BMO-MRW/retinal nerve fiber layer (RNFL) thickness and AL/SE

Summary

Introduction

Myopia is a common ocular disorder worldwide. It is estimated that there will be 4,758 million people with myopia in 2050 [1, 2]. Myopia is a risk factor for primary open-angle glaucoma (POAG) that can increase the risk of POAG by two- to three-fold [3, 4]. Since POAG can cause asymptomatic vision loss, early diagnosis of POAG in myopic patient is important. Diagnosis of POAG relies on evaluating optic disc, visual field, intraocular pressure (IOP), retinal nerve fiber layer (RNFL), and retinal ganglion cell (RGC) layer. Myopic eye is associated with tilted optic disc [5, 6], thinning of the RNFL [7] and RGC layer [8], increased intraocular pressure [4], and visual field defects [9]. The diagnosis of POAG in myopic patients is challenging

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