Optic neuritis and the neuro-ophthalmology of multiple sclerosis

Optical Coherence Tomography Angiography: Revolutionizing Clinical Diagnostics and Treatment in Central Nervous System Disease

Optical coherence tomography angiography (OCTA), as a new generation of non-invasive and efficient fundus imaging technology, can provide non-invasive assessment of vascular lesions in the retina and choroid. In terms of anatomy and development, the retina is referred to as an extension of the central nervous system (CNS). CNS diseases are closely related to changes in fundus structure and blood vessels, and direct visualization of fundus structure and blood vessels provides an effective "window" for CNS research. This has important practical significance for identifying the characteristic changes of various CNS diseases on OCTA in the future, and plays a key role in promoting early screening, diagnosis, and monitoring of disease progression in CNS diseases. This article reviews relevant fundus studies by comparing and summarizing the unique advantages and existing limitations of OCTA in various CNS disease patients, in order to demonstrate the clinical significance of OCTA in the diagnosis and treatment of CNS diseases.

Monoclonal antibodies in neuro-ophthalmology

Neuro-ophthalmologic diseases include a broad range of disorders affecting the afferent and efferent visual pathways. Recently, monoclonal antibody (mAb) therapies have emerged as a promising targeted approach in the management of several of these complex conditions. Here, we describe the mechanism-specific applications and advancements in neuro-ophthalmologic mAb therapies. The application of mAbs in neuro-ophthalmologic diseases highlights our increasing understanding of disease-specific mechanisms in autoimmune conditions such as neuromyelitis optica, thyroid eye disease, and myasthenia gravis. Due to the specificity of mAb therapies, applications in neuro-ophthalmologic diseases have yielded exceptional clinical outcomes, including both reduced rate of relapse and progression to disability, visual function preservation, and quality of life improvement. These advancements have not only expanded the range of treatable neuro-ophthalmologic diseases but also reduced adverse events and increased the response rate to treatment. Further research into neuro-ophthalmologic disease mechanisms will provide accurate and specific targeting of important disease mediators through applications of future mAbs. As our understanding of these diseases and the relevant therapeutic targets evolve, we will continue to build on our understanding of how mAbs interfere with disease pathogenesis, and how these changes improve clinical outcomes and quality of life for patients.

Macular Xanthophylls and Markers of the Anterior Visual Pathway among Persons with Multiple Sclerosis

BACKGROUND

Multiple sclerosis (MS) can cause retinal thinning among persons with MS with optic neuritis (MS-ON). Macular xanthophylls are carotenoids that comprise the macular pigment, filtering blue light and countering photo-oxidation. However, macular xanthophyll status and its implications for markers of neuroaxonal degeneration have not been examined in MS.

OBJECTIVES

This study characterized differences in macular and serum xanthophylls, and retinal morphometry [retinal nerve fiber layer thickness at the macular (mRNFL) and optic disc (odRNFL) and total macular volume (TMV)] in individuals with MS and healthy controls (HC). Associations between macular pigment optical density (MPOD) and retinal morphometry were also examined.

METHODS

Adults aged 45-64 y (HC, n = 42; MS, n = 40) participated in a cross-sectional study. MPOD was measured via heterochromatic flicker photometry. Retinal morphometry was measured via optical coherence tomography (OCT). Serum carotenoids were quantified using HPLC. Dietary carotenoids were collected using 7-d records. One-factor ANOVA was conducted to determine group effects on macular, serum, and dietary carotenoids. Partial correlations examined the relations between MPOD, retinal morphometry, diet, and serum carotenoids.

RESULTS

Relative to HC, persons with MS-ON had lower MPOD (Cohen's d = 0.84, P = 0.014), lower odRNFL (Cohen's d = 2.16, P <0.001), lower mRNFL (Cohen's d = 0.57, P = 0.028), and lower TMV (Cohen's d = 0.95, P = 0.011). MS without ON (MS) had lower odRNFL (Cohen's d = 0.93, P = 0.001) than HC and lower serum lutein than MS-ON subjects (Cohen's d = 0.65, P = 0.014). Among MS, MPOD was positively correlated with odRNFL thickness (ρ = 0.43, P = 0.049) and TMV (ρ = 0.45, P = 0.039), whereas odRNFL was negatively correlated with serum lutein (ρ = -0.68, P = 0.016) and zeaxanthin (ρ = -0.62, P = 0.028).

CONCLUSIONS

Persons with MS-ON exhibited poorer xanthophyll status in the macula and serum. MPOD was associated with beneficial anatomical features in the MS group. These findings warrant confirmation with larger cohorts and prospective trials to evaluate xanthophyll effects on the anterior visual pathway in MS.

Neuro-ophthalmologic manifestations of multiple sclerosis other than acute optic neuritis

Acute optic neuritis is the most common neuro-opthalmologic manifestation of multiple sclerosis (MS). Treatment with high-dose intravenous corticosteroids accelerates visual recovery, although it has no long-term visual benefit. MS has several others, less common, neuro-ophthalmological manifestations, where corticotherapy may not be the best treatment option. Neuro-ophthalmologic manifestations of MS other than optic neuritis can be divided in afferent and efferent visual pathways, acute and chronic and may be associated with drugs that are employed in MS. The authors propose is to review the neuro-ophthalmologic manifestations of multiple sclerosis other than optic neuritis. Recognition of these leads to a more targeted treatment and may prevent visual deterioration.

Impact of anesthesia exposure in early development on learning and sensory functions

Each year, millions of children undergo anesthesia, and both human and animal studies have indicated that exposure to anesthesia at an early age can lead to neuronal damage and learning deficiency. However, disorders of sensory functions were not reported in children or animals exposed to anesthesia during infancy, which is surprising, given the significant amount of damage to brain tissue reported in many animal studies. In this review, we discuss the relationship between the systems in the brain that mediate sensory input, spatial learning, and classical conditioning, and how these systems could be affected during anesthesia exposure. Based on previous reports, we conclude that anesthesia can induce structural, functional, and compensatory changes in both sensory and learning systems. Changes in myelination following anesthesia exposure were observed as well as the neurodegeneration in the gray matter across variety of brain regions. Disproportionate cell death between excitatory and inhibitory cells induced by anesthesia exposure can lead to a long-term shift in the excitatory/inhibitory balance, which affects both learning-specific networks and sensory systems. Anesthesia may directly affect synaptic plasticity which is especially critical to learning acquisition. However, sensory systems appear to have better ability to compensate for damage than learning-specific networks.

B-cell related biomarkers associated with severity of the first demyelinating event of acute optic neuritis

BACKGROUND

Optic neuritis (ON) is the most common cause of acute unilateral visual loss in young adults and frequently occurs as the presenting symptom of multiple sclerosis (MS). Recently, we reported activation of peripheral blood CD19 + ‏ B-cells in the early stage of ON. In the current study we aimed to identify peripheral blood ‏B-cell molecular markers associated with ON severity and visual outcome.

METHODS

Expression of B-cell related biomarkers were analysed in patients with the first clinical presentation of acute unilateral ON. Logarithm of the Minimum Angle of Resolution (LogMAR). visual acuity, Optical Coherence Tomography (OCT) imaging, Expanded Disability Status Scale (EDSS) visual score and visual evoked responses were evaluated at onset and visual acuity and EDSS visual score were repeated at 6 months post-ON.

RESULTS

Thirty patients with acute unilateral ON, 77% female, mean age 33 ± 2.0 years, were enroled in the study. Expression of CD19, CD79A and CD20 B-cell markers significantly correlated with LogMAR visual acuity of the affected eye (r = 0.44, p = 0.01, r = 0.37, p = 0.01 and r = 0.36, p = 0.04, respectively). The marker levels were elevated between 1.5 and 2.2-folds in the group with worse visual acuity (LogMAR>1.0) at onset (CD79A:×1.5, p = 0.013; CD19:×2.25, p = 0.007; CD20:×1.5, p = 0.015) and not correlated with 6 month visual outcome.

CONCLUSIONS

Among patient with a first event of acute ON, expression of B-cell biomarkers correlated with the severity of the disease. These results could add information on the role of B-cell dysfunction in the early stages of ON.

Neuropsychological Assessment in Multiple Sclerosis

Abstract. Neuropsychological deficits in multiple sclerosis (MS) are common. Over the past decades, many different procedures have been employed in diagnosing these deficits. Even though certain aspects of cognitive performance such as information processing speed and working memory may be affected more frequently than other cognitive functions, no specific deficit profile has been established in MS. This article provides an overview of the neuropsychological diagnostic procedures in MS and allows the reader to reach an informed decision on the applicability of specific procedures and the availability of study data in the context of MS. Additionally, it makes recommendations on the compilation of both screening procedures and extensive test batteries.

Capturing saccades in multiple sclerosis with a digitized test of rapid number naming

The King-Devick (K-D) test of rapid number naming is a visual performance measure that captures saccadic eye movements. Patients with multiple sclerosis (MS) have slowed K-D test times associated with neurologic disability and reduced quality of life. We assessed eye movements during the K-D test to identify characteristics associated with slowed times. Participants performed a computerized K-D test with video-oculography. The 25-Item National Eye Institute Visual Functioning Questionnaire (NEI-VFQ-25) and its 10-Item Neuro-Ophthalmic Supplement measured vision-specific quality of life (VSQOL). Among 25 participants with MS (age 37 ± 10 years, range 20-59) and 42 controls (age 33 ± 9 years, range 19-54), MS was associated with significantly longer (worse) K-D times (58.2 ± 19.8 vs. 43.8 ± 8.6 s, P = 0.001, linear regression models, accounting for age). In MS, test times were slower among patients with higher (worse) Expanded Disability Status Scale scores (P = 0.01). Average inter-saccadic intervals (ISI) were significantly longer in MS participants compared to controls (362 ± 103 vs. 286 ± 50 ms, P = 0.001), and were highly associated with prolonged K-D times in MS (P = 0.006). MS participants generated greater numbers of saccades (P = 0.007). VSQOL scores were reduced in MS patients with longer (worse) K-D times (P = 0.04-0.001) and longer ISI (P = 0.002-0.001). Patients with MS have slowed K-D times that may be attributable to prolonged ISI and greater numbers of saccades. The K-D test and its requisite eye movements capture VSQOL and make rapid number naming a strong candidate efferent visual performance measure in MS.

Efferent manifestations of multiple sclerosis

PURPOSE OF REVIEW

To review the various efferent visual system disorders associated with multiple sclerosis (MS).

RECENT FINDINGS

Studies have supported the use of internuclear ophthalmoplegia, a model to study effects of fatigue and heat in MS patients.

SUMMARY

There are a host of efferent ocular manifestations that can present throughout the course of MS. These may manifest as blurred vision, potentially misleading both the patient and clinician to suspect an afferent visual deficit. Other efferent symptoms include diplopia, oscillopsia, and vertigo. The efferent system can be divided into broad categories: supranuclear, internuclear, nuclear, and gaze-holding systems. This review will briefly touch on the anatomy as well as the signs and symptoms associated with MS-related dysfunction involving these systems.

Persistent visual impairment in multiple sclerosis: prevalence, mechanisms and resulting disability

Objective:

The objective of this article is to evaluate in multiple sclerosis (MS) patients the prevalence of persistent complaints of visual disturbances and the mechanisms and resulting functional disability of persistent visual complaints (PVCs).

Methods:

Firstly, the prevalence of PVCs was calculated in 303 MS patients. MS-related data of patients with or without PVCs were compared. Secondly, 70 patients with PVCs performed an extensive neuro-ophthalmologic assessment and a vision-related quality of life questionnaire, the National Eye Institute Visual Functionary Questionnaire (NEI-VFQ-25).

Results:

PVCs were reported in 105 MS patients (34.6%). Patients with PVCs had more frequently primary progressive MS (30.5% vs 13.6%) and more neuro-ophthalmologic relapses (1.97 vs 1.36) than patients without PVCs. In the mechanisms/disability study, an afferent visual and an ocular-motor pathways dysfunction were respectively diagnosed in 41 and 59 patients, mostly related to bilateral optic neuropathy and bilateral internuclear ophthalmoplegia. The NEI-VFQ 25 score was poor and significantly correlated with the number of impaired neuro-ophthalmologic tests.

Conclusion:

Our study emphasizes the high prevalence of PVC in MS patients. Regarding the nature of neuro-ophthalmologic deficit, our results suggest that persistent optic neuropathy, as part of the progressive evolution of the disease, is not rare. We also demonstrate that isolated ocular motor dysfunctions induce visual disability in daily life.

Review of subcutaneous interferon β-1a, delivered via the electronic self-injection device RebiSmart™, for the treatment of multiple sclerosis

Multiple sclerosis is a chronic disease requiring lifelong treatment with disease-modifying drugs that aim to prevent relapses and slow the progression of disability. The established first-line treatments for multiple sclerosis all require regular injections, and real-world observations suggest that long-term adherence to treatment is low. Indeed, poor adherence to disease-modifying drug treatment has been associated with poorer clinical outcomes. Autoinjectors have been developed to improve the success of self-injection, whilst also making injections more comfortable for patients, with the aim of minimizing obstacles to treatment adherence. RebiSmart™ is a new electronic autoinjector for subcutaneous administration of interferon β-1a (Rebif®) that includes several unique features designed to further reduce barriers to adherence, including a dosing log and adjustable comfort settings.

Correlation of optical coherence tomography with clinical and histopathological findings in experimental autoimmune uveoretinitis

Optical coherence tomography (OCT) is becoming the state-of-the-art method for the non-invasive imaging of a variety of ocular diseases. The aim of this study was to assess the application of OCT for the in vivo monitoring and follow-up of pathological changes during experimental autoimmune uveoretinitis (EAU) in rats. Initially we established OCT imaging in healthy brown Norway rats and correlated it with retinal histology. Subsequently, we induced EAU and imaged animals by OCT throughout the pre-peak, peak, and post-peak phases of the disease. The sensitivity of OCT imaging was determined by comparison with clinical EAU and histopathology scores obtained ex vivo at several time points throughout the disease course. Our data demonstrate that OCT imaging of the healthy rat retina closely correlates with histological observations and allows the clear visualization of all retinal layers. After induction of EAU, the first pathological changes could be detected by OCT at day (d) 8 post-immunization (p.i.) which corresponded to the time point of clinical disease onset. An increase in retinal thickness (RT) was detected from d10 p.i. onwards which peaked at d16 p.i. and decreased again to near control levels by d20 p.i. We introduce a novel semi-quantitative OCT scoring which correlates with histopathological findings and complements the clinical scores. Therefore, we conclude that OCT is an easily accessible, non-invasive tool for detection and follow-up of histopathological changes during EAU in rats. Indeed, significant differences in RT between different stages of EAU suggest that this OCT parameter is a sensitive marker for distinguishing disease phases in vivo.

Optic neuritis

AIMS

The aim of this study is to provide a clinical update on optic neuritis (ON), its association with multiple sclerosis (MS), and neuromyelitis optica (NMO).

METHODS

This study included a PubMed review of the literature written in the English language.

RESULTS

ON in adults is typically idiopathic or demyelinating, and is characterised by unilateral, subacute, painful loss of vision that is not associated with any systemic or other neurological symptoms. Demyelinating ON is associated with MS, and we review the key studies of ON including the ON treatment trial and several other MS treatment trials and NMO.

CONCLUSION

Acute demyelinating ON can occur in isolation or be associated with MS. Typical ON does not require additional evaluation other than cranial magnetic resonance imaging. NMO is likely a separate disorder from MS and the ON in NMO has a different treatment and prognosis.

METHODOLOGY

The authors conducted an English language search using Pubmed from the years 1964 to 2010 using the search terms 'ON', 'MS' and 'NMO'. The authors included original articles, review articles, and case reports, which revealed new aspects as far as epidemiology, histopathology, clinical manifestations, imaging, genetics, and treatment of ON. Titles were reviewed for topicality and full references were obtained. Letters to the editor, unpublished work, and abstracts were not included in this review.

Retinal architecture predicts pupillary reflex metrics in MS

OBJECTIVE

To study the relation of retinal nerve fiber layer thinning to clinical and physiologic measures of visual function in patients with MS or neuromyelitis optica and unilateral optic neuropathy.

METHODS

We studied a cohort of control subjects (n = 64) and patients (n = 24) with evidence of unilateral thinning of their average retinal nerve fiber layer as measured by optical coherence tomography in order to characterize the relationship between ganglion cell axonal degeneration and its impact upon vision and pupillary light reflex metrics using infrared pupillometry.

RESULTS

When compared to the normal fellow eye, and with respect to normal subjects' eyes, we confirmed significant abnormalities in retinal nerve fiber layer thickness, total macular volume, low-contrast letter acuity, and pupillary reflex metrics in the eye with the thinner retinal nerve fiber layer. For each -5% change in pupil diameter, there was a corresponding 7.1 Amicrom reduction in the average retinal nerve fiber layer thickness. There was a significant difference between the pupillary metric of percent change in diameter and a decrease in low-contrast letter acuity (P < 0.001). Each -5% change in pupil diameter was associated with a substantial 3.4 line loss of low-contrast letter acuity (P < 0.001). Each -5% change in pupil diameter was associated with a 0.2 mm(2) decrease in total macular volume (P < 0.001).

CONCLUSION

These findings further corroborate the hypothesis that the retina can be utilized as a model to advance our understanding of the mechanisms of axonal and neurodegeneration, and the corresponding impact of these processes upon the pathophysiology of MS and related disorders.