Functional Assessment of Outer and Middle Macular Layers in Multiple Sclerosis

Abstract

The involvement of macular preganglionic elements’ function, during the neurodegenerative process of multiple sclerosis (MS), is controversial. In this case-control observational and retrospective study, we assessed multifocal electroretinogram (mfERG) responses from 41 healthy Controls, 41 relapsing-remitting MS patients without optic neuritis (ON) (MS-noON Group) and 47 MS patients with ON: 27 with full recovery of high-contrast best corrected visual acuity (BCVA) (MS-ON-G Group) and 20 with poor recovery (between 0.2 and 1 LogMAR) of BCVA, (MS-ON-P Group). In the latter Group, Sd-OCT macular volumes and thicknesses of whole and inner and outer retina were measured. MfERG N1 and P1 implicit times (ITs), and N1-P1 response amplitude densities (RADs), were measured from concentric rings (R) with increasing foveal eccentricity: 0–5° (R1), 5–10° (R2), 10–15° (R3), 15–20° (R4), 20–25° (R5), and from retinal sectors (superior, nasal, inferior and temporal) between 0–15° and 0–25°. In the MS-ON-P Group, mean mfERG RADs detected from R1 (0–5°) and from the central nasal sector (0–15°) were significantly reduced (p < 0.01) with respect to those of the Control, MS-noON and MS-ON-G Groups. No other significant differences between Groups for any mfERG parameters were found. All Sd-OCT measurements, apart from the inner retina macular volume in the central 1 mm, were significantly reduced in MS-ON-P patients compared to Controls. The functional impairment in the MS-ON-P Group was associated but not correlated with structural changes of the outer and inner retinal layers in corresponding retinal Areas and Sectors. Our results suggest that in MS, exclusively after ON with poor recovery of BCVA, the neurodegenerative process can induce dysfunctional mechanisms involving photoreceptors and bipolar cells of the fovea and of the more central nasal macular area.

OCT Variability Prevents Their Use as Robust Biomarkers in Multiple Sclerosis

“…45 The involvement of macular preganglionic elements' function, during the neurodegenerative process of MS, is controversial and there are few references on this topic. 46 Regarding to FT results, our results show slightly lower FT values (between -7.62 μm to -16.17 μm depending of the OCT) in MS patients with a history of ON compared healthy eyes, than previously reported ones (-6.18 μm 95% CI between -8.07 μm to -4.28 μm). 2 However, FT thinning in MS patients without ON history (between -2.37 μm to -5.01 μm depending of the OCT) is closer to previous described thinning -2.15 μm 95% CI between -3.15 μm to -1.15 μm.…”

Macular Morpho-Functional and Visual Pathways Functional Assessment in Patients with Spinocerebellar Type 1 Ataxia with or without Neurological Signs

“…Macular structure and function can be assessed by Spectral domain Optical Coherence Tomography (Sd-OCT) and by multifocal electroretinogram (mfERG) recordings, respectively [18,19]. On the other hand, retinal ganglion cells (RGCs) axons, forming the optic nerve, can be morphologically studied by the analysis of the Sd-OCT retinal nerve fiber layer thickness (RNFL-T) [20], whereas the function of the innermost retinal layers (RGCs and their fibers) and of the neural conduction along the visual pathways can be assessed by Pattern ERG (PERG) [21,22] and Visual Evoked Potentials (VEP) [23,24] recordings, respectively.…”

Expression of poly(ADP-ribose) polymerase-1 gene and optical coherence tomography angiographic parameters among patients with multiple sclerosis

“…It was proved that MS could be associated with poor recovery of BCVA due to neurodegenerative process that may cause dysfunctional mechanisms involving the foveal photoreceptors and bipolar cells. 15 There was significant decrease in (CMT) in groups (A and B) compared with group C, which can be due to the preferential thinning of the central macula relative to the peripheral macular region in the eyes of patients with MS compared with normal eyes. The histological distribution of the nerve fibre layer and retinal ganglion cell in the macula, could be the cause of this macular thickness pattern.…”

“…It was proved that MS could be associated with poor recovery of BCVA due to neurodegenerative process that may cause dysfunctional mechanisms involving the foveal photoreceptors and bipolar cells. 15 …”