Validation of inter-eye difference thresholds in optical coherence tomography for identification of optic neuritis in multiple sclerosis

Optic nerve topography in multiple sclerosis diagnostic criteria: Existing knowledge and future directions

Current diagnostic criteria for multiple sclerosis (MS) do not consider the optic nerve as a typical topography for establishing the diagnosis. Recent studies have proved the utility of optic nerve magnetic resonance imaging, optical coherence tomography and visual evoked potentials in detecting optic nerve lesions during the early stages of MS. In addition, emerging evidence supports the inclusion of optic nerve topography as a fifth region to fulfil the dissemination in space criteria. Anticipating a modification in the McDonald criteria, it is crucial for neurologists to familiarize with the diagnostic properties of each test in detecting optic nerve lesions and understand how to incorporate them into the MS diagnostic process. Therefore, the objective of this article is to review the existing evidence supporting the use of these tests in the diagnostic process of MS and provide a practical algorithm that can serve as a valuable guide for clinical practice.

Delimiting MOGAD as a disease entity using translational imaging

The first formal consensus diagnostic criteria for myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) were recently proposed. Yet, the distinction of MOGAD-defining characteristics from characteristics of its important differential diagnoses such as multiple sclerosis (MS) and aquaporin-4 antibody seropositive neuromyelitis optica spectrum disorder (NMOSD) is still obstructed. In preclinical research, MOG antibody-based animal models were used for decades to derive knowledge about MS. In clinical research, people with MOGAD have been combined into cohorts with other diagnoses. Thus, it remains unclear to which extent the generated knowledge is specifically applicable to MOGAD. Translational research can contribute to identifying MOGAD characteristic features by establishing imaging methods and outcome parameters on proven pathophysiological grounds. This article reviews suitable animal models for translational MOGAD research and the current state and prospect of translational imaging in MOGAD.

Diagnostic Performance of Adding the Optic Nerve Region Assessed by Optical Coherence Tomography to the Diagnostic Criteria for Multiple Sclerosis

BACKGROUND AND OBJECTIVES

The optic nerve has been recommended as an additional region for demonstrating dissemination in space (DIS) in diagnostic criteria for multiple sclerosis (MS). The aim of this study was to investigate whether adding the optic nerve region as determined by optical coherence tomography (OCT) as part of the DIS criteria improves the 2017 diagnostic criteria.

METHODS

From a prospective observational study, we included patients with a first demyelinating event who had complete information to assess DIS and a spectral domain OCT scan obtained within 180 days. Modified DIS criteria (DIS + OCT) were constructed by adding the optic nerve to the current DIS regions based on validated thresholds for OCT intereye differences. Time to second clinical attack was the primary endpoint.

RESULTS

We analyzed 267 patients with MS (mean age 31.3 years [SD 8.1], 69% female) during a median observation period of 59 months (range: 13-98). Adding the optic nerve as a fifth region improved the diagnostic performance by increasing accuracy (DIS + OCT 81.2% vs DIS 65.6%) and sensitivity (DIS + OCT 84.2% vs DIS 77.9%) without lowering specificity (DIS + OCT 52.2% vs DIS 52.2%). Fulfilling DIS + OCT criteria (≥2 of 5 DIS + OCT regions involved) indicated a similar risk of a second clinical attack (hazard ratio [HR] 3.6, CI 1.4-14.5) compared with a 2.5-fold increased risk when fulfilling DIS criteria (HR 2.5, CI 1.2-11.8). When the analysis was conducted according to topography of the first demyelinating event, DIS + OCT criteria performed similarly in both optic neuritis and nonoptic neuritis.

DISCUSSION

Addition of the optic nerve, assessed by OCT, as a fifth region in the current DIS criteria improves diagnostic performance by increasing sensitivity without lowering specificity.

CLASSIFICATION OF EVIDENCE

This study provides Class II evidence that adding the optic nerve as determined by OCT as a fifth DIS criterion to the 2017 McDonald criteria improves diagnostic accuracy.

Retinal layer thickness predicts disability accumulation in early relapsing multiple sclerosis

BACKGROUND AND PURPOSE

This study was undertaken to investigate baseline peripapillary retinal nerve fiber layer (pRNFL) and macular ganglion cell and inner plexiform layer (GCIPL) thickness for prediction of disability accumulation in early relapsing multiple sclerosis (RMS).

METHODS

From a prospective observational study, we included patients with newly diagnosed RMS and obtained spectral-domain optical coherence tomography scan within 90 days after RMS diagnosis. Impact of pRNFL and GCIPL thickness for prediction of disability accumulation (confirmed Expanded Disability Status Scale [EDSS] score ≥ 3.0) was tested by multivariate (adjusted hazard ratio [HR] with 95% confidence interval [CI]) Cox regression models.

RESULTS

We analyzed 231 MS patients (mean age = 30.3 years, SD = 8.1, 74% female) during a median observation period of 61 months (range = 12-93). Mean pRNFL thickness was 92.6 μm (SD = 12.1), and mean GCIPL thickness was 81.4 μm (SD = 11.8). EDSS ≥ 3 was reached by 28 patients (12.1%) after a median 49 months (range = 9-92). EDSS ≥ 3 was predicted with GCIPL < 77 μm (HR = 2.7, 95% CI = 1.6-4.2, p < 0.001) and pRNFL thickness ≤ 88 μm (HR = 2.0, 95% CI = 1.4-3.3, p < 0.001). Higher age (HR = 1.4 per 10 years, p < 0.001), incomplete remission of first clinical attack (HR = 2.2, p < 0.001), ≥10 magnetic resonance imaging (MRI) lesions (HR = 2.0, p < 0.001), and infratentorial MRI lesions (HR = 1.9, p < 0.001) were associated with increased risk of disability accumulation, whereas highly effective disease-modifying treatment was protective (HR = 0.6, p < 0.001). Type of first clinical attack and presence of oligoclonal bands were not significantly associated.

CONCLUSIONS

Retinal layer thickness (GCIPL more than pRNFL) is a useful predictor of future disability accumulation in RMS, independently adding to established markers.

Association of paramagnetic rim lesions and retinal layer thickness in patients with multiple sclerosis

BACKGROUND

Paramagnetic rim lesions (PRLs) are chronic active lesions associated with a more severe disease course in multiple sclerosis (MS). Retinal layer thinning measured by optical coherence tomography (OCT) is a biomarker of neuroaxonal damage associated with disability progression in MS.

OBJECTIVE

We aimed to determine a potential association between OCT parameters (peripapillary retinal nerve fiber layer (pRNFL) ganglion cell-inner plexiform layer (GCIPL), inner nuclear layer (INL) thickness), and PRLs in patients with MS (pwMS).

METHODS

In this cross-sectional retrospective study, we included pwMS with both 3T brain MRI and an OCT scan. Regression models were calculated with OCT parameters (pRNFL, GCIPL, INL) as dependent variables, and the number of PRLs as an independent variable adjusted for covariates.

RESULTS

We analyzed data from 107 pwMS (mean age 34.7 years (SD 10.9), 64.5% female, median disease duration 6 years (IQR 1-13), median EDSS 1.5 (range 0-6.5)). Higher number of PRLs was associated with lower pRNFL (β = -0.18; 95% CI -0.98, -0.03; p = 0.038) and GCIPL thickness (β = -0.21; 95% CI -0.58, -0.02; p = 0.039).

CONCLUSION

The association between higher number of PRLs and lower pRNFL and GCIPL thicknesses provides additional evidence that pwMS with PRLs are affected by a more pronounced neurodegenerative process.

Diagnostic value of intereye difference metrics for optic neuritis in aquaporin-4 antibody seropositive neuromyelitis optica spectrum disorders

BACKGROUND

The novel optic neuritis (ON) diagnostic criteria include intereye differences (IED) of optical coherence tomography (OCT) parameters. IED has proven valuable for ON diagnosis in multiple sclerosis but has not been evaluated in aquaporin-4 antibody seropositive neuromyelitis optica spectrum disorders (AQP4+NMOSD). We evaluated the diagnostic accuracy of intereye absolute (IEAD) and percentage difference (IEPD) in AQP4+NMOSD after unilateral ON >6 months before OCT as compared with healthy controls (HC).

METHODS

Twenty-eight AQP4+NMOSD after unilateral ON (NMOSD-ON), 62 HC and 45 AQP4+NMOSD without ON history (NMOSD-NON) were recruited by 13 centres as part of the international Collaborative Retrospective Study on retinal OCT in Neuromyelitis Optica study. Mean thickness of peripapillary retinal nerve fibre layer (pRNFL) and macular ganglion cell and inner plexiform layer (GCIPL) were quantified by Spectralis spectral domain OCT. Threshold values of the ON diagnostic criteria (pRNFL: IEAD 5 µm, IEPD 5%; GCIPL: IEAD: 4 µm, IEPD: 4%) were evaluated using receiver operating characteristics and area under the curve (AUC) metrics.

RESULTS

The discriminative power was high for NMOSD-ON versus HC for IEAD (pRNFL: AUC 0.95, specificity 82%, sensitivity 86%; GCIPL: AUC 0.93, specificity 98%, sensitivity 75%) and IEPD (pRNFL: AUC 0.96, specificity 87%, sensitivity 89%; GCIPL: AUC 0.94, specificity 96%, sensitivity 82%). The discriminative power was high/moderate for NMOSD-ON versus NMOSD-NON for IEAD (pRNFL: AUC 0.92, specificity 77%, sensitivity 86%; GCIP: AUC 0.87, specificity 85%, sensitivity 75%) and for IEPD (pRNFL: AUC 0.94, specificity 82%, sensitivity 89%; GCIP: AUC 0.88, specificity 82%, sensitivity 82%).

CONCLUSIONS

Results support the validation of the IED metrics as OCT parameters of the novel diagnostic ON criteria in AQP4+NMOSD.

Diagnosis and classification of optic neuritis

There is no consensus regarding the classification of optic neuritis, and precise diagnostic criteria are not available. This reality means that the diagnosis of disorders that have optic neuritis as the first manifestation can be challenging. Accurate diagnosis of optic neuritis at presentation can facilitate the timely treatment of individuals with multiple sclerosis, neuromyelitis optica spectrum disorder, or myelin oligodendrocyte glycoprotein antibody-associated disease. Epidemiological data show that, cumulatively, optic neuritis is most frequently caused by many conditions other than multiple sclerosis. Worldwide, the cause and management of optic neuritis varies with geographical location, treatment availability, and ethnic background. We have developed diagnostic criteria for optic neuritis and a classification of optic neuritis subgroups. Our diagnostic criteria are based on clinical features that permit a diagnosis of possible optic neuritis; further paraclinical tests, utilising brain, orbital, and retinal imaging, together with antibody and other protein biomarker data, can lead to a diagnosis of definite optic neuritis. Paraclinical tests can also be applied retrospectively on stored samples and historical brain or retinal scans, which will be useful for future validation studies. Our criteria have the potential to reduce the risk of misdiagnosis, provide information on optic neuritis disease course that can guide future treatment trial design, and enable physicians to judge the likelihood of a need for long-term pharmacological management, which might differ according to optic neuritis subgroups.

Retinal layer thinning as a biomarker of long-term disability progression in multiple sclerosis

BACKGROUND

Peripapillary retinal nerve fibre layer and macular ganglion cell plus inner plexiform layer thinning are markers of neuroaxonal degeneration in multiple sclerosis.

OBJECTIVE

We aimed to investigate the value of peripapillary retinal nerve fibre layer and ganglion cell plus inner plexiform layer thinning for prediction of long-term disability.

METHODS

This is a 6-year prospective longitudinal study on 93 multiple sclerosis patients. Optical coherence tomography scans were performed at baseline, after 1, 2 and 6 years. Primary endpoint was disability progression after 6 years, defined as expanded disability status scale worsening and/or cognitive deterioration. Univariate and multivariate analysis was used to investigate the value of peripapillary retinal nerve fibre layer and ganglion cell plus inner plexiform layer to predict the primary endpoint.

RESULTS

A total of 57 (61.3%) patients had disability worsening, 40 (43.0%) expanded disability status scale worsening and 34 (36.6%) cognitive deterioration. Mean peripapillary retinal nerve fibre layer and ganglion cell plus inner plexiform layer baseline thickness were 93.0 and 75.2 µm, and mean annualised peripapillary retinal nerve fibre layer and ganglion cell plus inner plexiform layer thinning rates over 6 years were 1.3 and 1.6 µm, respectively. Univariate and multivariate analysis revealed lower peripapillary retinal nerve fibre layer and ganglion cell plus inner plexiform layer baseline thickness and higher annualised thinning rates in patients with disability progression after 6 years. Effects were more pronounced for ganglion cell plus inner plexiform layer and expanded disability status scale worsening than for peripapillary retinal nerve fibre layer models and cognitive deterioration.

CONCLUSION

Ganglion cell plus inner plexiform layer and peripapillary retinal nerve fibre layer measurements depict neurodegeneration and predict disability progression in multiple sclerosis.

Long-term Effect of Permanent Demyelination on Axonal Survival in Multiple Sclerosis

Background and Objectives

To investigate the long-term effect of permanent demyelination on axonal attrition by examining an association between intereye asymmetry of the multifocal visual evoked potential (mfVEP) latency delay and subsequent thinning of retinal ganglion cell axons in patients with a long-standing history of unilateral optic neuritis (ON).

Methods

Only patients with a significant degree of chronic demyelination (intereye latency asymmetry >5 ms) were included in this study. The level of optic nerve demyelination was estimated at baseline by the latency delay of mfVEP, while the degree of axonal loss was assessed by thinning of the retinal nerve fiber layer (RNFL) thickness between baseline and follow-up visits. Low-contrast visual acuity (LCVA) was also evaluated at baseline and follow-up. Patients were examined twice with an average interval of 6.1 ± 1.4 years.

Results

From 85 examined patients with multiple sclerosis, 28 satisfied inclusion criteria. Latency of the mfVEP was delayed, and RNFL thickness was reduced in ON eyes compared with fellow eyes at both visits. There was significant correlation between latency asymmetry and baseline or follow-up intereye RNFL thickness asymmetry. Intereye asymmetry of LCVA at baseline correlated with baseline latency asymmetry of mfVEP and baseline asymmetry of RNFL thickness. Latency of the mfVEP in ON eyes improved slightly during the follow-up period, whereas latency of the fellow eye remained stable. By contrast, RNFL thickness significantly declined in both ON and fellow eyes during the follow-up period. The rate of RNFL thinning in ON eyes, however, was more than 2 times faster compared with the fellow eyes (p < 0.001). Furthermore, baseline latency asymmetry significantly correlated with the rate of RNFL thinning in ON eyes during the follow-up (p < 0.001), explaining almost half of the variability of temporal RNFL progression. For each millisecond of latency delay (i.e., ∼0.5 mm of demyelination along the optic nerve), temporal RNFL thickness was annually reduced by 0.05%.

Discussion

Our study provides clear in vivo evidence that chronic demyelination significantly accelerates axonal loss. However, because this process is slow and its effect is mild, long-term monitoring is required to establish and confidently measure the neurodegenerative consequences of demyelination.

Retinal imaging with optical coherence tomography in multiple sclerosis: novel aspects

Optical coherence tomography (OCT) is of increasing interest in the clinical assessment of multiple sclerosis (MS) patients beyond the scope of clinical studies. In this narrative review, we discuss novel changes of OCT parameters during acute optic neuritis and the disease course of MS patients. OCT images document the changes of retinal layers during an episode of acute optic neuritis and can therefore provide valuable insights into the pathophysiology. Moreover, MS patients show progredient thinning of retinal layers throughout the disease. The thinning is accelerated through relapses as well as disease progression without relapse. The OCT parameters are also associated with clinical outcome parameters, including disability, cognitive function, and brain atrophy. The impact of disease-modifying therapies on OCT parameters is the subject of ongoing research and depends on the agent used. Additional data are still necessary before OCT parameters can be implemented in the clinical standard of care of MS patients.

Association of Cerebrospinal Fluid Parameters and Neurofilament Light Chain With Retinal Nerve Fiber Layer Thickness in Multiple Sclerosis

Introduction

Multiple sclerosis (MS) pathophysiology comprises both inflammatory and neurodegenerative characteristics. Cerebrospinal fluid (CSF) analysis allows for assessment of inflammation while neurofilament light chain can indicate neuroaxonal damage. Retinal thinning is a robust prognostic biomarker for neurodegeneration in MS. To date, an association between CSF parameters upon MS diagnosis and retinal thinning has not been investigated.

Aims and Objectives

We aimed to determine whether CSF parameters are associated with the evolution of retinal layer thinning in people with MS (pwMS).

Methods

For this longitudinal observational study, we investigated pwMS from the Vienna MS database (VMSD), who had undergone (1) a diagnostic lumbar puncture (LP) between 2015 and 2020, and (2) simultaneous optical coherence tomography (OCT) and/or (3) a follow-up OCT scan. Linear stepwise regression models were calculated with OCT parameters (peripapillary retinal nerve fiber layer [pRNFL] thickness at LP and at follow-up, annualized loss of pRNFL thickness [aLpRNFL]) as a dependent variable, and CSF parameters (white blood cell [WBC] count, total protein [_CSFTP], CSF/serum albumin ratio [Q_alb], intrathecal synthesis of immunoglobulins, neurofilament light chain [NfL] in both CSF and serum [_CSFNfL/sNfL]) as independent variables adjusted for age, sex, and disease duration.

Results

We analyzed 61 pwMS (median age 30.0 years [interquartile range 25.5–35.0], 57.4% female, median disease duration 1.0 month [IQR 0–2.0] before LP, median follow-up 1.9 years [IQR 1.1–3.5]). _CSFNfL and sNfL measurements were available in 26 and 31 pwMS, respectively. pRNFL thickness at LP was inversely associated with the CSF WBC count (β = −0.36; 95% CI −0.51, −0.08; p = 0.008). We did not find any association between other CSF parameters, including _CSFNfL, sNfL, and aLpRNFL.

Conclusions

Increased WBC count as an indicator of acute inflammation and blood-brain-barrier breakdown seems to be associated with the amount of retinal thickness already lost at the time of LP. However, neither routine CSF parameters nor a singular NfL measurement allows the prediction of future retinal thinning.

Retinal and Choriocapillary Vascular Changes in Early Stages of Multiple Sclerosis: A Prospective Study

Optical Coherence Tomography Angiography (OCTA) abnormalities occur in multiple sclerosis (MS) over the course of the disease. OCTA investigations at early MS stages are lacking. We aimed to investigate vessel density in macular and papillary regions over two years after an initial demyelinating event (IDE). Vessel density was analyzed in superficial, deep, choriocapillaris and radial peripapillary plexus at baseline, and after one and two years. We also evaluated structural OCT parameter changes of the ganglion cell complex (GCC) and retinal nerve fiber layer (RNFL). We evaluated 30 eyes from 15 IDE patients (7 females, 8 males, mean age 28.4 ± 9.6 years) and 30 eyes from 15 healthy controls. After 2 years, we reported in the IDE group a reduced vessel density in the superficial capillary plexus, deep capillary plexus and radial peripapillary capillary plexus with respect to the baseline (coeff. β = −2.779, p = 0.013; coeff. β = −4.055, p = 0.018 and coeff. β = −2.687, p ≤ 0.001; respectively), while GCC and RNFL thicknesses did not change. Vessel density reduction was not associated with an expanded disability status scale (EDSS) change, relapse occurrence or magnetic resonance imaging activity. The analysis of healthy controls did not reveal any impairment in OCT and OCTA parameters over 2 years of follow-up. Retinal vascular loss occurs in patients with an IDE independently from clinical and radiological disease activity. Retinal vessel density could represent a novel early biomarker to monitor the MS pathological burden.

Retinal Oxygen Metabolism and Haemodynamics in Patients With Multiple Sclerosis and History of Optic Neuritis

Vascular changes and alterations of oxygen metabolism are suggested to be implicated in multiple sclerosis (MS) pathogenesis and progression. Recently developed in vivo retinal fundus imaging technologies provide now an opportunity to non-invasively assess metabolic changes in the neural retina. This study was performed to assess retinal oxygen metabolism, peripapillary capillary density (CD), large vessel density (LVD), retinal nerve fiber layer thickness (RNFLT) and ganglion cell inner plexiform layer thickness (GCIPLT) in patients with diagnosed relapsing multiple sclerosis (RMS) and history of unilateral optic neuritis (ON). 16 RMS patients and 18 healthy controls (HC) were included in this study. Retinal oxygen extraction was modeled using O₂ saturations and Doppler optical coherence tomography (DOCT) derived retinal blood flow (RBF) data. CD and LVD were assessed using optical coherence tomography (OCT) angiography. RNFLT and GCIPLT were measured using structural OCT. Measurements were performed in eyes with (MS+ON) and without (MS-ON) history for ON in RMS patients and in one eye in HC. Total oxygen extraction was lowest in MS+ON (1.8 ± 0.2 μl O₂/min), higher in MS-ON (2.1 ± 0.5 μl O₂/min, p = 0.019 vs. MS+ON) and highest in HC eyes (2.3 ± 0.6 μl O₂/min, p = 0.002 vs. MS, ANOVA p = 0.031). RBF was lower in MS+ON (33.2 ± 6.0 μl/min) compared to MS-ON (38.3 ± 4.6 μl/min, p = 0.005 vs. MS+ON) and HC eyes (37.2 ± 4.7 μl/min, p = 0.014 vs. MS+ON, ANOVA p = 0.010). CD, LVD, RNFLT and GCIPL were significantly lower in MS+ON eyes. The present data suggest that structural alterations in the retina of RMS patients are accompanied by changes in oxygen metabolism, which are more pronounced in MS+ON than in MS-ON eyes. Whether these alterations promote MS onset and progression or occur as consequence of disease warrants further investigation. Clinical Trial Registration: ClinicalTrials.gov registry, NCT03401879.

Optical Coherence Tomography in the Differential Diagnosis of Patients with Multiple Sclerosis and Patients with MRI Nonspecific White Matter Lesions

In the differential diagnosis of nonspecific white matter lesions (NSWMLs) detected on magnetic resonance imaging (MRI), multiple sclerosis (MS) should be taken into consideration. Optical coherence tomography (OCT) is a promising tool applied in the differential diagnostic process of MS. We tested whether OCT may be useful in distinguishing between MS and NSWMLs patients. In patients with MS (n = 41) and NSWMLs (n = 19), the following OCT parameters were measured: thickness of the peripapillary Retinal Nerve Fibre Layer (pRNFL) in superior, inferior, nasal, and temporal segments; thickness of the ganglion cell-inner plexiform layer (GCIPL); thickness of macular RNFL (mRNFL); and macular volume (MV). In MS patients, GCIPL was significantly lower than in NSWMLs patients (p = 0.024). Additionally, in MS patients, mRNFL was significantly lower than in NSWMLs patients (p = 0.030). The average segmental pRNFL and MV did not differ between MS and NSWMLs patients (p > 0.05). GCIPL and macular RNFL thinning significantly influenced the risk of MS (18.6% [95% CI 2.7%, 25.3%]; 27.4% [95% CI 4.5%, 62.3%]), and reduced GCIPL thickness appeared to be the best predictor of MS. We conclude that OCT may be helpful in the differential diagnosis of MS and NSWMLs patients in real-world settings.

Retinal layer thinning predicts treatment failure in relapsing multiple sclerosis

Background and purpose

Peripapillary retinal nerve fiber layer (pRNFL) and macular ganglion cell plus inner plexiform layer (GCIPL) thinning are markers of neuroaxonal degeneration in multiple sclerosis (MS), which is reduced by disease‐modifying treatment (DMT). We aimed to investigate the potential of pRNFL and GCIPL thinning for prediction of DMT failure in relapsing MS (RMS).

Methods

In this 4‐year prospective observational study on 113 RMS patients, pRNFL and GCIPL were measured at DMT initiation and after 12 months (M12) and 24 months (M24). Treatment failure was defined as 6‐month confirmed Expanded Disability Status Scale (EDSS) progression and/or Symbol Digit Modalities Test (SDMT) worsening. Optimal cutoff values for predicting treatment failure were determined by receiver operating characteristic analyses and hazard ratios (HRs) by multivariable Cox regression adjusting for age, sex, disease duration, EDSS/SDMT, and DMT class.

Results

Thinning of GCIPL >0.5 μm/year at M24 showed superior value for treatment failure prediction (HR: 4.5, 95% confidence interval [CI]: 1.8–7.6, p < 0.001; specificity 91%, sensitivity 81%), followed by GCIPL >0.5 μm at M12 (odds ratio [OR]: 3.9, 95% CI: 1.4–6.9, p < 0.001; specificity 85%, sensitivity 78%), and pRNFL ≥2 μm/year at M24 (OR: 3.7, 95% CI: 1.1–6.5, p = 0.023; specificity 84%, sensitivity 69%), whereas pRNFL at M12 was not predictive.

Conclusions

GCIPL, and to a lesser degree pRNFL, thinning predicts disability progression after DMT initiation and may be a useful and accessible biomarker of treatment failure in RMS.

Evaluation of Retinal Layer Thickness Parameters as Biomarkers in a Real-World Multiple Sclerosis Cohort

Purpose

Retinal layer thickness parameters measured by optical coherence tomography (OCT) are emerging biomarkers of neuroaxonal degeneration and inflammation in multiple sclerosis (MS). We aimed to evaluate the value of retinal layer thickness for prediction of disability worsening and relapse in a real-world MS cohort.

Patients and Methods

For this longitudinal observational study, we included MS patients with spectral-domain OCT scans available and ≥1 year of clinical follow-up. The value of peripapillary retinal nerve fiber layer (pRNFL), macular ganglion-cell-and-inner-plexiform-layer (GCIPL) and inner nuclear layer (INL) thickness for prediction of disability worsening and relapse during the observation period was tested by multivariate models.

Results

We analyzed 60 MS patients during a mean observation period of 2.9 years (SD 1.8). Lower baseline thickness of GCIPL (cut-off <77µm; HR 4.1, p=0.001) and pRNFL (cut-off ≤88µm; HR 3.1, p=0.019) were associated with an increased risk of disability worsening. Longitudinally, mean thinning rates were −0.8µm/year (SD 1.6) for GCIPL, −0.6µm/year (SD 3.5) for pRNFL. GCIPL thinning ≥1.0µm/year and pRNFL >1.5µm/year is associated with higher likelihood of disability worsening (HR 5.7, p=0.009 and HR 6.8, p=0.003, respectively). INL thickened in patients with relapse by a mean 0.9µm while thinning by 0.3µm in patients without relapse (p=0.04). In multivariate analyses, INL thickening was associated with an increased probability of relapse (OR 17.8, p=0.023).

Conclusion

Cross-sectional and longitudinal measurement of GCIPL and pRNFL thinning is reliable as a biomarker of disability worsening in a real-world setting. Change of INL thickness is a promising marker of relapse, i.e. inflammatory activity.

Optical Coherence Tomography and Optical Coherence Tomography Angiography Findings After Optic Neuritis in Multiple Sclerosis

Background: In people with multiple sclerosis (MS), optic neuritis (ON) results in inner retinal layer thinning, and reduced density of the retinal microvasculature.

Objective: To compare inter-eye differences (IEDs) in macular optical coherence tomography (OCT) and OCT angiography (OCTA) measures in MS patients with a history of unilateral ON (MS ON) vs. MS patients with no history of ON (MS non-ON), and to assess how these measures correlate with visual function outcomes after ON.

Methods: In this cross-sectional study, people with MS underwent OCT and OCTA. Superficial vascular plexus (SVP) density of each eye was quantified using a deep neural network. IEDs were calculated with respect to the ON eye in MS ON patients, and with respect to the right eye in MS non-ON patients. Statistical analyses used mixed-effect regression models accounting for intra-subject correlations.

Results: We included 43 MS ON patients (with 92 discrete OCT/OCTA visits) and 14 MS non-ON patients (with 24 OCT/OCTA visits). Across the cohorts, mean IED in SVP density was −2.69% (SD 3.23) in MS ON patients, as compared to 0.17% (SD 2.39) in MS non-ON patients (p = 0.002). When the MS ON patients were further stratified according to time from ON and compared to MS non-ON patients with multiple cross-sectional analyses, we identified that IED in SVP density was significantly increased in MS ON patients at 1–3 years (p = < 0.001) and >3 years post-ON (p < 0.001), but not at <3 months (p = 0.21) or 3–12 months post-ON (p = 0.07), while IED in ganglion cell + inner plexiform layer (GCIPL) thickness was significantly increased in MS ON patients at all time points post-ON (p ≦ 0.01 for all). IED in SVP density and IED in GCIPL thickness demonstrated significant relationships with IEDs in 100% contrast, 2.5% contrast, and 1.25% contrast letter acuity in MS ON patients (p < 0.001 for all).

Conclusions: Our findings suggest that increased IED in SVP density can be detected after ON in MS using OCTA, and detectable changes in SVP density after ON may occur after changes in GCIPL thickness. IED in SVP density and IED in GCIPL thickness correlate well with visual function outcomes in MS ON patients.

Retinal layer thinning is reflecting disability progression independent of relapse activity in multiple sclerosis

Background

PIRA (progression independent of relapse) has emerged as a term to quantify the proportion of disability worsening due to non-inflammatory neurodegenerative processes in multiple sclerosis (MS).

Objective

To determine the impact of PIRA on retinal thinning, a biomarker of neuroaxonal degeneration in MS, in comparison to traditional disability worsening and relapse.

Methods

In a 4-year, prospective observational study including 171 relapsing MS (RMS) patients, retinal thinning was determined by annual spectral-domain optical coherence tomography measuring macular ganglion-cell-and-inner-plexiform-layer (GCIPL) and peripapillary-retinal-nerve-fibre-layer (pRNFL). PIRA was defined as an expanded disability status scale (EDSS) or symbol digit modalities test (SDMT) worsening confirmed after 24 weeks with no relapse in the 30 days before or after the disability worsening.

Results

Each PIRA event was associated with a mean additional loss of GCIPL (1.8 µm) and pRNFL (1.9 µm), similar to the impact of EDSS and SDMT worsening. Overall relapse and relapse without subsequent EDSS worsening did not influence retinal thinning, while a relapse with EDSS worsening was associated with an additional loss of GCIPL (1.3 µm) and pRNFL (1.4 µm).

Conclusions

PIRA is associated with retinal thinning, likely reflecting neurodegenerative processes, not directly associated with focal inflammation. It might be a clinical measure to identify MS patients with ongoing MS-associated neurodegeneration.

Ocular fixation and macular integrity by microperimetry in multiple sclerosis

PURPOSE

To characterize the fixation and macular integrity of subjects with multiple sclerosis (MS) with and without previous optic neuritis (ON) using microperimetry (MP).

METHODS

Fifty-five eyes of MS patients, subdivided into three groups (28 eyes without ON, 16 with previous ON, and 11 eyes with previous ON in the contralateral eye), and 43 healthy eyes were enrolled (January-November 2018). All cases were evaluated using the MAIA microperimeter (Centervue), analyzing the following parameters: average macular threshold (AT), fixation indexes (P1 and P2), bivariate contour ellipse area (BCEA) for 95% and 63% of points, and horizontal (H) and vertical (V) axes of the ellipse of fixation.

RESULTS

All MS groups showed a significant reduced AT compared with the control group (p < 0.001). This reduction was more representative (p < 0.001) in eyes with previous ON. No statistically significant differences were found between MS patients with and without previous ON (p > 0.05). Mean AT was correlated with the examination time in all three groups (between ρ = - 0.798 p < 0.001 and ρ = - 0.49 p < 0.001). Significant differences in fixation parameters were only found between control and MS with ON groups (p < 0.02). The ratio of the disease showed a significant correlation with fixation parameters in MS groups (p < 0.02), but not with AT.

CONCLUSIONS

In MS patients, macular sensitivity is altered, especially in eyes with previous ON. Likewise, a fixational instability is present in MS patients with ON, with more increase of the V axis of the fixation area than of the H. The ratio of the disease also affects the patient fixation pattern.

Should I stop or should I go on? Disease modifying therapy after the first clinical episode of multiple sclerosis

Introduction

Treatment with disease-modifying therapies (DMT) in patients with clinically isolated syndrome (CIS) represents standard care in multiple sclerosis (MS) patients nowadays. Since a proportion of patients may show no evidence of disease activity (NEDA) after some time of treatment, the question might arise about the risks of stopping DMT.

Methods

We present a cohort of 49 patients who started DMT immediately after CIS and had no evidence of disease activity (NEDA-3) for at least five years before discontinuation of therapy. Thereafter, patients underwent clinical and MRI follow-up for at least five consecutive years.

Results

Of 49 patients discontinuing DMT, 53% (n = 26) had NEDA for at least further five years, while 47% (n = 23) showed either a relapse/disease progression (18.4%, n = 9), MRI activity (14.3%, n = 7) or both (14.3%, n = 7). The main predictive factor for sustained NEDA was age at DMT termination. Patients aged > 45 years had a significantly lower risk of disease reactivation (13% vs. 54% in patients aged < 45 years, p < 0.001) after DMT discontinuation.

Discussion

In CIS patients with immediate DMT after their first clinical episode, older age at the time of DMT discontinuation is the main predictive factor for sustained NEDA status.