Background: Neuronal loss in the retina has been demonstrated pathologically in eyes of patients with multiple sclerosis (MS). In vivo, MS eyes have reduced total macular volumes by optical coherence tomography (OCT). Using a high-resolution spectral-domain OCT, this pilot study used a manual method to measure ganglion cell layer (GCL) volumes and to determine the relation of these volumes to visual function in MS eyes.
Methods: Sixteen eyes of 8 patients with MS and 8 eyes of 5 disease-free control participants were studied using fast macular OCT scans performed with Spectralis OCT (Heidelberg Engineering). Visual function tests of low-contrast letter acuity and high-contrast visual acuity were administered.
Results: MS patient eyes had significantly lower GCL volumes than the control eyes (P < 0.001 vs controls, generalized estimating equation regression models accounting for age and within-patient intereye correlations). Within the MS group, eyes with a history of optic neuritis (ON, n = 4) had significantly lower GCL volumes than MS eyes with no ON history (P < 0.001). In contrast to measures of high-contrast visual acuity (P = 0.14), decreased GCL volumes were associated with worse performance on low-contrast letter acuity testing (P = 0.003).
Conclusions: This pilot study has characterized thinning of the GCL in MS patient eyes, particularly in those with a history of acute ON, which corresponded to a reduced performance on low-contrast letter acuity testing. Studies utilizing computerized segmentation algorithms will continue to facilitate the detection of GCL loss on a larger scale and provide important information in vivo on the role and timing of neuronal vs axonal loss in MS eyes.
Departments of Neurology (ECD, KMG, DJS, LST, SLG, LJB), Ophthalmology (SLG, LJB), and Epidemiology (LJB), University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania; Department of Neurology (EMF), University of Texas Southwestern Medical Center, Dallas, Texas; and Department of Neurology (PAC), The Johns Hopkins University School of Medicine, Baltimore, Maryland.
Supported by the National MS Society Grants PP1115, RG 3208-A-1, and RG 3428-A/2 (LJB), the National MS Society Translational Research Partnership Grant TR 3760-A-3 (PAC, LJB), the National Institutes of Health/National Eye Institute Grants K24 EY 014136 and R01 EY 019473 (LJB), the McNeill Foundation, the DADs Foundation, the Penn Clinical Neuroscience Track Summer Fellowship (ECD), and the Foundation of the Consortium of MS Centers (DJS).
Dr E. M. Frohman has received speaking and consulting honoraria from Biogen-Idec, Novartis, TEVA, and Acorda. Dr P. A. Calabresi has received personal compensation for consulting and serving on scientific advisory boards from Biogen-Idec, Teva, and Novartis and has received research funding from companies Biogen-Idec, Teva, EMD Serono, Vertex, Genentech, Abbott, and Bayer. Dr. S. L. Galetta has received speaking and consulting honoraria from Biogen-Idec, Novartis, and Teva. Dr L. J. Balcer has received speaking and consulting honoraria from Biogen-Idec, Bayer, and Novartis.
Address correspondence to Laura J. Balcer, MD, MSCE, 3 East Gates Building, Neurology, 3400 Spruce Street, Philadelphia, PA; E-mail: email@example.com