Retinal atrophy in relation to visual functioning and vision-related quality of life in patients with multiple sclerosis

Disease Course of Clinically Isolated Optic Neuritis

BACKGROUND AND OBJECTIVES

Optic neuritis is the most common optic neuropathy in young adults and a frequent manifestation of multiple sclerosis. Its clinical course is pertinent to the design of visual pathway neuroprotection trials.

METHODS

This is a secondary analysis of longitudinal data from the TONE trial, which included 103 patients from 12 German academic tertiary centers with acute unilateral optic neuritis as a clinically isolated syndrome and baseline high-contrast visual acuity <0.5 decimal. Patients were randomized to 1,000 mg methylprednisolone i.v./d plus either erythropoietin (33,000 IU/d) or placebo (saline solution) for 3 days. They were followed up at standardized intervals with a battery of tests including high-contrast visual acuity, low-contrast letter acuity, contrast sensitivity, visual fields, visual evoked potentials, and retinal optical coherence tomography. At 6 months, participants answered a standardized questionnaire on vision-related quality of life (NEI-VFQ 25). We describe the disease course with mixed-effects piecewise linear models and calculate structure-function correlations using Pearson r. Because erythropoietin had no effect on the visual system, we use pooled (treatment-agnostic) data.

RESULTS

Patients experienced initial rapid and then decelerating improvements of visual function with thinning of inner and thickening of outer retinal layers. At 6 months, visual parameters were positively correlated with inner and negatively correlated with outer retinal thickness changes. Peripapillary retinal nerve fiber layer thinning predominantly occurred in sectors without previous swelling. At 6 months, macular ganglion cell and inner plexiform layer thinning was weakly correlated with the P100 peak time (r = -0.11) and moderately correlated with the amplitude of visual evoked potentials (r = 0.35). Only functional outcomes were at least moderately correlated with vision-related quality of life.

DISCUSSION

The longitudinal data from this large study cohort may serve as a reference for the clinical course of acute optic neuritis. The pattern of correlation between visual evoked potentials and inner retinal thinning may argue that the latter is mostly due to ganglion cell loss, rather than dysfunction. Visual pathway neuroprotection trials with functional outcomes are needed to confirm that candidate drugs will benefit patients' vision-related quality of life.

TRIAL REGISTRATION INFORMATION

ClinicalTrials.gov, NCT01962571.

Application of the International Interocular Difference Thresholds into Practice: Localising the Patient Experience

Demyelinating diseases of the central nervous system (CNS) often have neuro-ophthalmological manifestations, and retinal examination can be helpful in making the diagnosis. The latest iteration of optical coherence tomography (OCT)-based criteria for optic neuritis in multiple sclerosis has been developed in the research realm, but its application to clinical practice, and to the more uncommon demyelinating diseases requires further study. The ability to use OCT data to distinguish between various CNS demyelinating disorders could provide additional paraclinical tools to accurately diagnose patients. Furthermore, neuro-ophthalmological testing can define the extent of inflammatory damage in the CNS, independent of patient-reported history. New referrals for OCT at a tertiary multiple sclerosis and neuro-immunology referral centre (n = 167) were analysed retrospectively for the self-reporting of optic neuritis, serological test results, and diagnosis. Only approximately 30% of patients with a clinical history of unilateral optic neuritis solely had a unilateral optic neuropathy, nearly 40% of those subjects actually having evidence of bilateral optic neuropathies. Roughly 30% of patients reporting a history of bilateral optic neuritis did not have any evidence of structural disease, with 20% of these patients having a separate, intervenable diagnosis noted on macular scans. OCT is a useful adjunct diagnostic tool in the evaluation of demyelinating disease and has the ability to aid in a more accurate diagnosis for patients. Application of the international interocular difference thresholds to a clinical patient population generally reproduces the original results, emphasising their appropriateness. The analysis distinguishing the demyelinating diseases needs to be replicated in a blinded, multi-centre setting.

Neuroprotective Effects of Novel Treatments on Acute Optic Neuritis—A Meta-Analysis

Optic neuritis, inflammation of the optic nerve, can cause visual impairment through retinal nerve fiber layer (RNFL) degeneration. Optical coherence tomography could serve as a sensitive noninvasive tool for measuring RNFL thickness and evaluating the neuroprotective effects of treatment. We conducted a meta-analysis to compare RNFL loss between novel add-on treatments and corticosteroid therapy at least 3 months after acute optic neuritis. The outcome measures were mean differences (MDs) in (1) RNFL thickness compared with the baseline in the affected and unaffected eye and (2) LogMAR visual acuity (VA). Seven studies involving five novel agents (memantine, erythropoietin, interferon-beta, phenytoin, and clemastine) were analyzed. When compared with the baseline RNFL thickness of the affected eye, the neuroprotective effects of novel add-on treatments could not be demonstrated. The difference in visual outcomes was also not significant between the two treatment groups. One study revealed that phenytoin has the potential to alleviate RNFL loss when the baseline thickness of the unaffected eye is considered. Larger randomized controlled trials with suitable outcome measures are warranted to evaluate the neuroprotective effects of novel treatments. Further studies should also tailor therapies to specific patient populations and investigate a more targeted treatment for acute optic neuritis.

Optic neuritis in Asian type opticospinal multiple sclerosis (OSMS-ON) in a non-Asian population: A functional-structural paradox

BACKGROUND

Biomarkers have improved the classification of autoimmune inflammatory disorders, including optic neuritis (ON) as a frequent presentation of multiple sclerosis, neuromyelitis spectrum disorders, MOG antibody-related disease (MOGAD), and opticospinal multiple sclerosis (OSMS). The phenotype of OSMS in non-Asian populations is less well known.

OBJECTIVE

We investigated the clinical features and prognosis of OSMS-ON in a Brazilian cohort.

METHODS

This was a single-center cohort study of patients from Rio de Janeiro (Brazil) with OSMS. All individuals were MOG- and AQP4-seronegative, clinically diagnosed with ON, and had magnetic resonance imaging-confirmed transverse myelitis (TM). Subjects and healthy controls (HCs) were assessed for visual acuity (logMAR VA), automated perimetry mean deviation (MD), intraocular pressure, and spectral-domain optical coherence tomography (OCT), followed by automated retinal layer segmentation of the peripapillary retinal nerve fiber layer (pRNFL) and macular ganglion cell and inner plexiform layer (mGCIPL). Receiver operator characteristic curves were plotted and the area under the curve (AUC) was calculated for group comparisons of retinal asymmetry of the pRNFL and mGCIPL.

RESULTS

The 30 patients with OSMS were predominantly female and white. The mean age was 48 years (range 20-70 years). Unilateral ON was the index event in 83.3% of patients. Over the average 18-year follow-up period, there were 89 relapses of ON. In individuals with OSMS, the average VA was 0.07±0.14 in the right eye (RE) and 0.13±0.30 in the left eye (LE). The MD was -5.37±5.88 dB and -5.23±3.34 dB for the RE and LE, respectively. There was a significant cumulative loss of VA (p = 0.0003) and MD (p = 0.0001) with a higher number of recurrent episodes. Atrophy of the pRNFL thickness was significant in OSMS (RE, 78.62 ± 16.01 µm; LE, 79.86 ± 13.79 µm) relative to the HC group (RE, 98.87 ± 10.68 µm; LE, 97.87 ± 10.85 µm, p = 0.0001). Likewise, there was significant mGCIPL atrophy in patients with OSMS (RE, 74.96 ± 14.46 µm; LE, 73.88 ± 13.79 µm) relative to the HC group (RE, 90.50 ± 6.74 µm; LE, 90.41± 6.89 µm; p = 0.0001). Retinal asymmetry, inter-eye percentage, and absolute differences accurately separated patients with unilateral ON from HCs (AUC=0.89 and AUC=0.85, respectively).

CONCLUSION

A structural-functional paradox was found in OSMS with a high diagnostic value for a novel metric based on retinal asymmetry. The functional visual outcome are excellent despite significant structural damage to the inner retinal layers in patients with a high ON relapse rate and long-term bilateral sequential involvement.

Subclinical anterior optic pathway involvement in early multiple sclerosis and clinically isolated syndromes

Optical coherence tomography (OCT) is gaining increasing relevance in the assessment of patients with multiple sclerosis. Converging evidence point to the view that neuro-retinal changes, in eyes without acute optic neuritis, reflect inflammatory and neurodegenerative processes taking place throughout the CNS. The present study aims at exploring the usefulness of OCT as a marker of inflammation and disease burden in the earliest phases of the disease. Thus, a cohort of 150 consecutive patients underwent clinical, neurophysiological and brain MRI assessment as well as lumbar puncture as part of their diagnostic workup for a neurological episode suggestive of inflammatory CNS disorder; among those 32 patients had another previous misdiagnosed episode. For the present study, patients also received a visual pathway assessment (OCT, visual evoked potentials, visual acuity), measurement of CSF inflammatory markers (17 cytokines-chemokines, extracellular vesicles of myeloid origin), and dosage of plasma neurofilaments. Subclinical optic nerve involvement is frequently found in clinically isolated syndromes by visual evoked potentials (19.2%). OCT reveals ganglion cell layer asymmetries in 6.8% of patients; retinal fibre layer asymmetries, despite being more frequent (17.8%), display poor specificity. The presence of subclinical involvement is associated with a greater disease burden. Second, ganglion cell layer thinning reflects the severity of disease involvement even beyond the anterior optic pathway. In fact, the ganglion cell layer in eyes without evidence of subclinical optic involvement is correlated with Expanded Disability Status Scale, low contrast visual acuity, disease duration, brain lesion load, presence of gadolinium enhancing lesions, abnormalities along motor and somatosensory evoked potentials, and frequency of CSF-specific oligoclonal bands. Third, the inner nuclear layer thickens in a post-acute (1.1-3.7 months) phase after a relapse, and this phenomenon is counteracted by steroid treatment. Likewise, a longitudinal analysis on 65 patients shows that this swelling is transient and returns to normal values after 1 year follow-up. Notwithstanding, the clinical, MRI, serological and CSF markers of disease activity considered in the study are strictly associated with one another, but none of them are associated with the inner nuclear layer. Our findings challenge the current hypothesis that the inner nuclear layer is an acute phase marker of inflammatory activity. The present study suggests that instrumental evidence of subclinical optic nerve involvement is associated with a greater disease burden in clinically isolated syndrome. Neuro-retinal changes are present since the earliest phases of the disease and yield important information regarding the neurodegenerative and inflammatory processes occurring in the CNS.

A model for interrogating the clinico-radiological paradox in multiple sclerosis: Internuclear ophthalmoplegia

Background and purpose

The clinico‐radiological paradox in multiple sclerosis (MS) is well recognized, relevant and yet poorly understood. The suitability of an in vivo model for the clinico‐radiological paradox was tested, using internuclear ophthalmoplegia (INO) and the medial longitudinal fasciculus (MLF).

Methods

In this cross‐sectional study lesions of the MLF were rated by an experienced MS neuroradiologist blinded to all other information. The presence of an INO was objectively determined by a validated infrared oculography protocol (DEMoNS). Clinical information, including the National Eye Institute Visual Function Questionnaire, was obtained.

Results

This study included 202 patients with MS. The clinico‐radiological paradox occurred in 50 patients (25%). This consisted of 45 patients having an INO without an MLF lesion and five patients with an MLF lesion but without an INO. The visual function overall score was related to the presence of an INO (p = 0.016), but not to MLF lesions seen on magnetic resonance imaging (MRI) (p = 0.207). A consensus list of potential causes for the clinico‐radiological paradox was compiled and the MRI images were deposited in a repository.

Conclusion

This study provides an objective and quantitative model to investigate the clinico‐radiological paradox. Our data suggest that pathology of the MLF is more frequently detected and more clinically relevant by infrared oculography than by MLF lesion rating on MRI.

Advances in ophthalmic structural and functional measures in multiple sclerosis: do the potential ocular biomarkers meet the unmet needs?

PURPOSE OF REVIEW

Multiple sclerosis is a heterogeneous disorder. Biomarkers to monitor disease activities are highly desirable especially because of the recent shift toward personalized medicine that coincides with the expansion of disease-modifying therapy. The visual system is highly involved in multiple sclerosis, and the rapid advancement of ophthalmic techniques has boosted the development of potential ocular biomarkers for multiple sclerosis management.

RECENT FINDINGS

Recent studies have found that the rapid thinning of the peripapillary retinal nerve fiber layer and ganglion cell-inner plexiform layer (GCIPL) occurs in the progressive stage. Furthermore, the inter-eye thickness difference of the GCIPL could be used in identifying unilateral optic neuritis to facilitate the early diagnosis of multiple sclerosis. Moreover, the retinal microvascular alterations measured as vessel density were found to be related to the disability and visual function, although a standardized protocol to measure retinal microvascular alterations has not been well established. Additionally, aberrant ocular motility, such as fixation microsaccades, can be used to measure disability objectively.

SUMMARY

The fast expansion of potential ocular biomarkers measured as retinal microstructural, microvascular, and ocular motility changes may facilitate the diagnosis and management of multiple sclerosis.

Low Contrast Visual Acuity Might Help to Detect Previous Optic Neuritis

Optic neuritis (ON) has been considered to be an important factor in the diagnosis of multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD), making ON detection increasingly critical for early diagnosis. Furthermore, subclinical ONs presenting no distinct decrease in visual acuity can be missed. Low contrast visual acuity (LC-VA) is known to be able to capture visual loss not seen in conventional high-contrast visual acuity (HC-VA) in MS. Therefore, to increase the sensitivity of ON detection, we investigated the advantage of LC-VA over conventional HC-VA. One hundred and eight patients with demyelinating disease (35 MS, 73 NMOSD) with ON at least 3 months prior and 35 controls underwent neuro-ophthalmic evaluation, including best-corrected conventional high contrast visual acuity (HC-VA) and 2.5% and 1.25% low contrast visual acuity (LC-VA). Receiver operating characteristic (ROC) curve analysis and the area under the curve (AUC) of various visual functions were used to determine the most relevant visual function test for the detection of optic nerve involvement. Additionally, the optimal cutoff point was obtained from the Youden index (J-index) as the points with the best sensitivity-specificity balance. When distinguishing ON from non-ON, the area under the ROC curve (AUC) was highest for the 2.5% LC-VA (0.835, P < 0.001; sensitivity 71.5%, specificity 88.6%), while it was 0.710 (P < 0.001) for the HC-VA and 0.770 (P < 0.001) for the 1.25% LC-VA. In discriminating between controls and ON, the AUC was also highest for the 2.5% LC-VA 0.754 (P < 0.001; sensitivity 71.5%, specificity 78.5%), while it was 0.719 (P < 0.001) for HC-VA and 0.688 (P < 0.001) for 1.25% LC-VA. In eyes with a history of ON (n = 137), the HC-VA and 2.5% LC-VA were abnormal in 64.2 and 71.5%, respectively (P < 0.001), with their combination detecting abnormalities in approximately 85.4% (P < 0.001). The 2.5% LC-VA was superior to HC-VA in detecting ON when distinguishing ON from non-ON or control. The 2.5% LC-VA might be a useful, feasible, and rapid method to detect ON. Furthermore, combining 2.5% LC-VA with conventional HC-VA would be better for detecting optic nerve involvements.

Quantification of Visual Fixation in Multiple Sclerosis

Purpose

Eye movement abnormalities are common in multiple sclerosis (MS), and infrared oculography is a noninvasive method for quantification. This study aims to describe and classify abnormalities of visual fixation and their clinical relevance in MS.

Methods

A validated standardized infrared oculography protocol, Demonstrate Eye Movement Networks with Saccades, was used for quantifying gaze stability during a fixation task in MS patients and healthy controls. Saccadic intrusions, gaze drift, and stability of fixation around the drift line were used to subclassify MS patients by performing receiver operating characteristic analyses of different parameters. The relationship between the presence of abnormalities of fixation and visual functioning was analyzed using logistic regression models, which was adjusted for possible confounders.

Results

This cross-sectional study included 213 subjects with MS and 57 healthy controls. Square wave jerk abnormalities were present in 24% of MS patients. The prevalence was higher in more disabled subjects. The presence of larger square wave jerks (with a higher amplitude) in the MS patients was related to complaints of focusing on stationary objects (odds ratio, 2.2; P = 0.035) and a lower vision-related quality of life (odds ratio, 2.56; P = 0.012).

Conclusions

This study provided a comprehensive overview of the characteristics of problems with visual fixation in subjects with MS. The most important and most common finding was the presence of larger square wave jerks during fixation, which was related to visual functioning in daily life.

Visual Function and Disability Are Associated With Focal Thickness Reduction of the Ganglion Cell-Inner Plexiform Layer in Patients With Multiple Sclerosis

Purpose

The purpose of this study was to visualize the topographic thickness patterns of the intraretinal layers and their associations with clinical manifestations in patients with multiple sclerosis (MS).

Methods

Ninety-four eyes of 47 relapsing-remitting MS patients without history of optic neuritis were imaged using optical coherence tomography and compared with 134 eyes of 67 healthy subjects. Volumetric data centered on the fovea were segmented to obtain the thickness maps of six intraretinal layers. The thickness measurements partitioned using the Early Treatment Diabetic Retinopathy Study (ETDRS) partition were correlated to the Expanded Disability State Scale (EDSS) and Sloan low contrast visual acuity (LCVA). The receiver-operating characteristics (ROC) curves were calculated to obtain the area under the ROC curves (AUCs).

Results

The ganglion cell-inner plexiform layer (GCIPL) showed horseshoe-like thickness reduction profoundly at the nasal sector. The most profound thickness reduction zone (circular area, diameter = 1 mm) was located at 2 mm in the nasal sector and 0.4 mm inferior from the fovea, named the “M zone.” The thickness reduction of the M zone was −7.3 μm in MS eyes, which was the most profound alteration, compared to any ETDRS sectors. The AUC of the M zone was 0.75. The relationship between the thickness of the M zone and EDSS (r = −0.59, P < 0.001) or 2.5% LCVA (r = 0.51, P < 0.001) were ranked as the strongest relation compared to any ETDRS sectors.

Conclusions

This is the first study, to our knowledge, to visualize focal thickness alteration of GCIPL and reveal its relationship to visual function and disability in patients with MS without history of optic neuritis.

Discriminative power of intra-retinal layers in early multiple sclerosis using 3D OCT imaging

OBJECTIVE

To evaluate volumetric changes and discriminative power of intra-retinal layers in early-stage multiple sclerosis (MS) using a 3D optical coherence tomography (OCT) imaging method based on an in-house segmentation algorithm.

METHODS

3D analysis of intra-retinal layers was performed in 71 patients with early-stage MS (mean disease duration 2.2 ± 3.5 years) at baseline and 40 healthy controls (HCs). All patients underwent a follow-up OCT scan within 23 ± 9 months. Patients with a clinical episode of optic neuritis (ON) more than 6 months prior to study entrance were compared with patients who never experienced clinical symptoms of an ON episode (NON).

RESULTS

Significantly decreased total retinal volume (TRV), macular retinal nerve fiber layer (mRNFL) and ganglion cell-inner plexiform layer (GCIPL) volumes were detected in ON patients compared to NON patients (all p values < 0.05) at baseline. Each parameter on its own allowed identification of prior clinical ON based on a discriminative model (ROC analysis). Over time, TRV decreased in both ON (p = 0.013) and NON patients (p = 0.002), whereas mRNFL volume (p = 0.028) decreased only in ON and GCIPL volume (p = 0.003) decreased only in NON patients.

CONCLUSION

Our 3D-OCT data demonstrated that TRV, mRNFL and GCIPL allow discrimination between ON and NON patients in a cross-sectional analysis. However, the subsequent retinal atrophy pattern diverges in the initial phase of MS: Prior ON promotes sustained axonal thinning over time indicated by mRNFL loss, whereas longitudinal measurement of GCIPL volume better depicts continuous retrograde neurodegeneration in NON patients in early-stage MS.

Retinal nerve fiber layer and ganglion cell layer changes on optical coherence tomography in early multiple sclerosis and optic neuritis cases

PURPOSE

To study the retinal nerve fiber layer (RNFL) and ganglion cell layer (GCL) changes on optical coherence tomography in early multiple sclerosis (MS) patients.

METHODS

A prospective cohort study was conducted at a tertiary care center. Patients of early MS (expanded disability status scale <3) with or without optic neuritis (ON) and idiopathic ON were included. Twenty age-matched individuals were taken as controls. Changes in RNFL and GCL thickness were evaluated along with the correlation with visual function parameters such as visual acuity, contrast sensitivity, and visual evoked response at first visit and again at six months.

RESULTS

Forty-four patients of MS with or without ON (24 and 20 patients respectively), 29 patients with idiopathic ON, and 20 healthy controls constituted the cohorts. Mean LogMAR best-corrected visual acuity was found to be significantly reduced in all groups except fellow eyes (FE) of ON group. Mean values of average RNFL thickness and values in superior, temporal, and inferior quadrant were significantly reduced. Similarly, overall mean values of average GCL-inner plexiform layer (IPL) thickness and values in superior, superonasal, superotemporal, inferonasal, and inferotemporal quadrant were significantly reduced in all groups except FE of ON group (P < 0.05). All the visual parameters significantly correlated with GCL + IPL thickness.

CONCLUSION

GCL + IPL thickness is a more sensitive clinical structural marker than RNFL in early MS with/without ON and ON patients and correlates with all the visual parameters better than RNFL thickness.

Predictors of vision impairment in Multiple Sclerosis

Visual impairment significantly alters the quality of life of people with Multiple Sclerosis (MS). The objective of this study was to identify predictors (independent variables) of visual outcomes, and to define their relationship with neurological disability and retinal atrophy when assessed by optical coherence tomography (OCT). We performed a cross-sectional analysis of 119 consecutive patients with MS, assessing vision using high contrast visual acuity (LogMar), 2.5% and 1.25% low contrast visual acuity (Sloan charts), and color vision (Hardy-Rand-Rittler plates). Quality of vision is a patient reported outcome based on an individual's unique perception of his or her vision and was assessed with the Visual Functioning Questionnaire-25 (VFQ-25) with the 10 neuro-ophthalmologic items. MS disability was assessed using the expanded disability status scale (EDSS), the MS functional composite (MSFC) and the brief repetitive battery-neuropsychology (BRB-N). Retinal atrophy was assessed using spectral domain OCT, measuring the thickness of the peripapillar retinal nerve fiber layer (pRNFL) and the volume of the ganglion cell plus inner plexiform layer (GCIPL). The vision of patients with MS was impaired, particularly in eyes with prior optic neuritis. Retinal atrophy (pRNFL and GCIPL) was closely associated with impaired low contrast vision and color vision, whereas the volume of the GCIPL showed a trend (p = 0.092) to be associated with quality of vision. Multiple regression analysis revealed that EDSS was an explanatory variable for high contrast vision after stepwise analysis, GCIPL volume for low contrast vision, and GCIPL volume and EDSS for color vision. The explanatory variables for quality of vision were high contrast vision and color vision. In summary, quality of vision in MS depends on the impairment of high contrast visual acuity and color vision due to the disease.