Reduced Cone Density Is Associated with Multiple Sclerosis

Comparison of macular changes according to the etiology of optic neuritis: a cross-sectional study

AIM

To compare the macular structure including foveal thickness among patients with optic neuritis (ON) according to the etiology and to investigate the possible correlation between structural and visual outcomes.

METHODS

In this retrospective cross-sectional study, the clinical data of patients with aquaporin-4 immunoglobulin G-related ON (AQP4 group, 40 eyes), myelin oligodendrocyte glycoprotein IgG-related ON (MOG group, 31 eyes), and multiple sclerosis-related ON (MS group, 24 eyes) were obtained. The retinal thickness of the foveal, parafoveal and perifoveal regions were measured. Visual acuity (VA), visual field index and mean deviation were measured as visual outcomes.

RESULTS

The AQP4 group showed a significantly thinner fovea (226.4±13.4 µm) relative to the MOG (236.8±14.0 µm, P=0.015) and MS (238.9±14.3 µm, P=0.007) groups. The thickness in the parafoveal area also was thinner in the AQP4 group, though the difference in perifoveal retinal thickness was not significant. Foveal thickness was correlated with VA in the AQP4 group (coefficient ρ=-0.418, P=0.014), but not in the MOG and MS groups (P=0.218 and P=0.138, respectively). There was no significant correlation between foveal thickness and visual field test in all three groups.

CONCLUSION

The significant thinning in the fovea and parafoveal areas in the AQP4 group compared to the MOG and MS groups are found. Additionally, macular changes in AQP4-ON show a significant correlation with VA. The results provide the possibility that retinal structural damage could reflect functional damage in AQP4-ON, distinct from MOG-ON and MS-ON.

Non-invasive in vivo imaging of brain and retinal microglia in neurodegenerative diseases

Microglia play crucial roles in immune responses and contribute to fundamental biological processes within the central nervous system (CNS). In neurodegenerative diseases, microglia undergo functional changes and can have both protective and pathogenic roles. Microglia in the retina, as an extension of the CNS, have also been shown to be affected in many neurological diseases. While our understanding of how microglia contribute to pathological conditions is incomplete, non-invasive in vivo imaging of brain and retinal microglia in living subjects could provide valuable insights into their role in the neurodegenerative diseases and open new avenues for diagnostic biomarkers. This mini-review provides an overview of the current brain and retinal imaging tools for studying microglia in vivo. We focus on microglia targets, the advantages and limitations of in vivo microglia imaging approaches, and applications for evaluating the pathogenesis of neurological conditions, such as Alzheimer's disease and multiple sclerosis.

Differential Study of Retinal Thicknesses in the Eyes of Alzheimer's Patients, Multiple Sclerosis Patients and Healthy Subjects

Multiple sclerosis (MS) and Alzheimer's disease (AD) cause retinal thinning that is detectable in vivo using optical coherence tomography (OCT). To date, no papers have compared the two diseases in terms of the structural differences they produce in the retina. The purpose of this study is to analyse and compare the neuroretinal structure in MS patients, AD patients and healthy subjects using OCT. Spectral domain OCT was performed on 21 AD patients, 33 MS patients and 19 control subjects using the Posterior Pole protocol. The area under the receiver operating characteristic (AUROC) curve was used to analyse the differences between the cohorts in nine regions of the retinal nerve fibre layer (RNFL), ganglion cell layer (GCL), inner plexiform layer (IPL) and outer nuclear layer (ONL). The main differences between MS and AD are found in the ONL, in practically all the regions analysed (AUROCFOVEAL = 0.80, AUROCPARAFOVEAL = 0.85, AUROCPERIFOVEAL = 0.80, AUROC_PMB = 0.77, AUROCPARAMACULAR = 0.85, AUROCINFERO_NASAL = 0.75, AUROCINFERO_TEMPORAL = 0.83), and in the paramacular zone (AUROCPARAMACULAR = 0.75) and infero-temporal quadrant (AUROCINFERO_TEMPORAL = 0.80) of the GCL. In conclusion, our findings suggest that OCT data analysis could facilitate the differential diagnosis of MS and AD.