Abstract
Objective: To investigate functional and structural retinal changes in multiple sclerosis patients (MS) with history of optic neuritis (HON) and without (NHON). Methods: In this cross-sectional study, 12 NHON, 11 HON and 14 control participants were included for multifocal pattern electroretinography (mfPERG) and optical coherence tomography (OCT) measurements. MfPERG was recorded (Veris Science) with a circular dartboard pattern (22° radius) comprising 36 elements. Amplitude and latencies of the mfPERG components N35, P50 and N95 were assessed. Macular OCT scans were acquired to determine ganglion cell layer (GCL) and inner plexiform layer thickness (IPL) and optic disc OCT scans were acquired to assess the total (G), papillomacular bundle (PMB), and temporal (T) peripapillary retinal nerve fiber layer thickness (pRNFL). Group differences and crossmodal associations were assessed. Results: For mfPERG, only the central ring’s N95 amplitude [F(2,34)=7.8, p=0.008] was altered, i.e. a reduction in HON and NHON vs. controls [mean (±SE) difference: -0.5 ± 0.13 μV (p=0.002) and NHON -0.3 ± 0.13 μV (p=0.048), respectively]. For OCT, parafoveal GCL [F(2,34)=13.8, p≤0.001] and IPL thicknesses [F(2,34)=8.1, p=0.003] were lower in HON vs. controls [mean difference: 11.6 ± 2.2 μm (p≤0.001) and 5.7 ± 1.4 μm (p≤0.001), respectively]. Perifoveal GCL thickness [F(2,34)=6.5, p=0.008] was also significantly reduced in HON vs. controls. The T [F(2,32)=5.2, p=0.022] and PMB [F(2,32)=6.5, p=0.012] pRNFL sectors showed reductions in HON vs. controls [mean difference: 16.2 ± 5.1 μm (p=0.01) and 13.5 ±3.9 μm (p=0.004), respectively]. Crossmodal correlations were observed only for the central N95 amplitude and perifoveal GCL thickness (r:-0.47, p=0.036). Conclusion: Central N95 amplitudes were reduced in MS, both in HON and NHON groups. As the N95 is associated with the ganglion cell axons[1], these finding might indicate early foveal axonal dysfunction not only in HON, but also in NHON patients. [1]Bach et al Exp Eye Res. https://doi.org/10.1016/j.exer.2018.01.021