Retinal Thickness Asymmetry in Highly Myopic Eyes with Early Stage of Normal-Tension Glaucoma.

Pei-Wen Lin,Yi-Chieh Poon,Hsueh-Wen Chang,Bao Jian Fan

doi:10.1155/2021/6660631

Pei-Wen Lin, Yi-Chieh Poon + Show 2 more

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https://doi.org/10.1155/2021/6660631

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Abstract

Purpose To investigate the retinal thickness asymmetry parameters of circumpapillary retinal nerve fiber layer (cpRNFL) and macular layers measured by spectral-domain optical coherence tomography in highly myopic (HM) patients with an early stage of normal-tension glaucoma (NTG). Methods This cross-sectional study included 55 eyes of HM patients with early NTG and 37 eyes of HM normal participants. High myopia was defined as spherical equivalence more myopic than −6 diopters. Thickness differences and asymmetry indices (AIs) of cpRNFL between superior and inferior corresponding parts and thickness differences and AIs of the total macular layer (TML) and inner macular layers between superior and inferior hemispheres were calculated. The areas under the receiver operating characteristic curves (AROCs) were analyzed and compared. Results In the cpRNFL asymmetry analysis, the thickness differences and AIs of cpRNFL between temporal-superior and temporal-inferior sectors (P < 0.0001 and P < 0.0001, respectively) and between superior and inferior quadrants (P = 0.002 and P < 0.0001, respectively) were significantly different between HM control subjects and HM NTG patients. In the macular asymmetry analysis, the thickness difference and AI of TML were significantly different between superior and inferior hemispheres (P < 0.0001 and P < 0.0001, respectively). The thickness difference and AI of the macular ganglion cell layer (mGCL) were significantly different between superior and inferior hemispheres (P < 0.0001 and P < 0.0001, respectively). The AROCs for thickness difference of TML (0.845) and thickness difference of mGCL (0.773) were comparable to AROCs for average cpRNFL thickness (0.842), macular retinal nerve fiber layer thickness (mRNFL) thickness (0.871), and mGCL thickness (0.822). Conclusion In our study, HM NTG patients had retinal thickness asymmetry in cpRNFL, TML, and mGCL. The diagnostic capabilities for thickness asymmetry of TML and mGCL were comparable to the diagnostic capabilities for cpRNFL thickness, mRNFL thickness, and mGCL thickness. Asymmetry analysis of retinal thickness can be an adjunctive tool for the early detection of HM NTG.

Highlights

Glaucoma is the second leading cause of blindness worldwide [1]
Regarding the macular thickness asymmetry assessment, the thickness differences and asymmetry indices (AIs) of the total macular layer (TML) and macular ganglion cell layer (mGCL) between superior and inferior hemispheres were significantly different between highly myopic (HM) control subjects and patients with HM normal-tension glaucoma (NTG). e thickness differences and AIs of macular retinal nerve fiber layer thickness (mRNFL) and macular inner plexiform layer (mIPL) did not show significant differences between HM control subjects and patients with HM NTG
In comparison with the diagnostic capability of each parameter, there were no significant differences in the areas under the receiver operating characteristic curves (AROCs) among circumpapillary retinal nerve fiber layer (cpRNFL) thickness, mRNFL thickness, mGCL thickness, thickness difference of TML, and thickness difference of mGCL. e diagnostic capabilities for AIs of TML and mGCL were better than the diagnostic capabilities for thickness differences of TML and mGCL. e results are shown in Table 4 and Figure 3

Summary

Introduction

Glaucoma is the second leading cause of blindness worldwide [1]. It is characterized by progressive loss of retinal ganglion cells (RGC), decreased thickness of retinal nerve fiber layer (RNFL), increased cupping of the optic disc, thinning of the neuroretinal rim with notching of optic nerve head (ONH), and specific visual field (VF) defects. e retinal ganglion somas, axons, and dendrites are usually damaged in glaucomatous optic neuropathy. Glaucoma is the second leading cause of blindness worldwide [1] It is characterized by progressive loss of retinal ganglion cells (RGC), decreased thickness of retinal nerve fiber layer (RNFL), increased cupping of the optic disc, thinning of the neuroretinal rim with notching of optic nerve head (ONH), and specific visual field (VF) defects. The distribution of thickness parameters for cpRNFL is usually overlapped between normal and glaucomatous eyes. Yamada et al reported an overlap of 68 of 92 eyes (73.9%) in the thickness of the cpRNFL between normal and glaucomatous eyes [2]. The distribution of RGC and the retinal thickness profiles are symmetric between the upper and lower retinal hemispheres [3, 4].

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