Visual Function and Disability Are Associated With Focal Thickness Reduction of the Ganglion Cell-Inner Plexiform Layer in Patients With Multiple Sclerosis

Abstract

PurposeThe purpose of this study was to visualize the topographic thickness patterns of the intraretinal layers and their associations with clinical manifestations in patients with multiple sclerosis (MS).MethodsNinety-four eyes of 47 relapsing-remitting MS patients without history of optic neuritis were imaged using optical coherence tomography and compared with 134 eyes of 67 healthy subjects. Volumetric data centered on the fovea were segmented to obtain the thickness maps of six intraretinal layers. The thickness measurements partitioned using the Early Treatment Diabetic Retinopathy Study (ETDRS) partition were correlated to the Expanded Disability State Scale (EDSS) and Sloan low contrast visual acuity (LCVA). The receiver-operating characteristics (ROC) curves were calculated to obtain the area under the ROC curves (AUCs).ResultsThe ganglion cell-inner plexiform layer (GCIPL) showed horseshoe-like thickness reduction profoundly at the nasal sector. The most profound thickness reduction zone (circular area, diameter = 1 mm) was located at 2 mm in the nasal sector and 0.4 mm inferior from the fovea, named the “M zone.” The thickness reduction of the M zone was −7.3 μm in MS eyes, which was the most profound alteration, compared to any ETDRS sectors. The AUC of the M zone was 0.75. The relationship between the thickness of the M zone and EDSS (r = −0.59, P < 0.001) or 2.5% LCVA (r = 0.51, P < 0.001) were ranked as the strongest relation compared to any ETDRS sectors.ConclusionsThis is the first study, to our knowledge, to visualize focal thickness alteration of GCIPL and reveal its relationship to visual function and disability in patients with MS without history of optic neuritis.

Focal Thickness Reduction of the Ganglion Cell-Inner Plexiform Layer Best Discriminates Prior Optic Neuritis in Patients With Multiple Sclerosis

“…The discrimination power of the GCIPL thickness in the U Zone was compared with the ETDRS partitions and the M Zone, which was previously defined in MS eyes without a history of ON. 15 The previously defined 15 M zone was located at nasal 1.98 mm and inferior 0.42 mm from the fovea with a circular area (Fig. 8).…”

“…The focal thickness reduction zone in the intraretinal layers generally represents the area that is most seriously affected by certain diseases (Table 2). 15,16,[26][27][28][29][30][31][32][33] Different thickness reduction patterns were documented in different systemic conditions, such as Alzheimer's disease, 16 and ocular disorders, such as glaucoma. [26][27][28] These characteristic patterns often provide disease-specific information and better discrimination powers compared with averaged thickness.…”

“…However, it is hard to exclude subclinical ON clinically, which occurs with high incidence in patients with MS. [3][4][5] The averaged thicknesses of the GCIPL and pRNFL that are used in intereye approaches 11,13,14 may not be sensitive enough to identify optic nerve damage. Because the distribution of the neural fiber and ganglion cells are not even, [15][16][17] and the alterations in these neural layers are not even. 15,16 The average thicknesses of these layers using arbitrary partitions, such as the elliptical partition, which is commonly used in the clinic, may not well define the focal thickness alterations 11,13,14 and could render the moderate discrimination power when using the intereye thickness difference approach.…”

“…Because the distribution of the neural fiber and ganglion cells are not even, [15][16][17] and the alterations in these neural layers are not even. 15,16 The average thicknesses of these layers using arbitrary partitions, such as the elliptical partition, which is commonly used in the clinic, may not well define the focal thickness alterations 11,13,14 and could render the moderate discrimination power when using the intereye thickness difference approach.…”

“…The visualization and quantitative analysis of topographic thickness patterns of intraretinal layers may identify the most profound focal thickness alterations and help in the development of sensitive markers of prior ON in patients with MS. A previous study of MS patients without a history of ON Copyright 2019 The Authors iovs.arvojournals.org j ISSN: 1552-5783 (MSNON) reported that the most profound thickness alteration was located in the inferior nasal area of the GCIPL, named the ''M Zone,'' and provided the highest discrimination power and strongest correlations to visual function and disease disability. 15 However, whether eyes with a history of ON in patients with MS share similar thickness patterns is not known. The purpose of the present study was to visualize the topographic thickness patterns of intraretinal layers and evaluate their discrimination performance and relationships with clinical manifestations in patients with MS and a history of ON.…”