Clinically isolated syndromes suggestive of multiple sclerosis: an optical coherence tomography study

Using personalized prognosis in the treatment of relapsing multiple sclerosis: A practical guide

The clinical course of multiple sclerosis (MS) is highly variable among patients, thus creating important challenges for the neurologist to appropriately treat and monitor patient progress. Despite some patients having apparently similar symptom severity at MS disease onset, their prognoses may differ greatly. To this end, we believe that a proactive disposition on the part of the neurologist to identify prognostic “red flags” early in the disease course can lead to much better long-term outcomes for the patient in terms of reduced disability and improved quality of life. Here, we present a prognosis tool in the form of a checklist of clinical, imaging and biomarker parameters which, based on consensus in the literature and on our own clinical experiences, we have established to be associated with poorer or improved clinical outcomes. The neurologist is encouraged to use this tool to identify the presence or absence of specific variables in individual patients at disease onset and thereby implement sufficiently effective treatment strategies that appropriately address the likely prognosis for each patient.

Disorders of vision in multiple sclerosis

Multiple sclerosis (MS) is a neurological inflammatory disorder known to attack the heavily myelinated regions of the nervous system including the optic nerves, cerebellum, brainstem and spinal cord. This review will discuss the clinical manifestations and investigations for MS and other similar neurological inflammatory disorders affecting vision, as well as the effects of MS treatments on vision. Assessment of visual pathways is critical, considering MS can involve multiple components of the visual pathway, including optic nerves, uvea, retina and occipital cortex. Optical coherence tomography is increasingly being recognised as a highly sensitive tool in detecting subclinical optic nerve changes. Magnetic resonance imaging (MRI) is critical in MS diagnosis and in predicting long-term disability. Optic neuritis in MS involves unilateral vision loss, with characteristic pain on eye movement. The visual loss in neuromyelitis optica spectrum disorder tends to be more severe with preferential altitudinal field loss, chiasmal and tract lesions are also more common. Other differential diagnoses include chronic relapsing inflammatory optic neuropathy and giant cell arteritis. Leber's hereditary optic neuropathy affects young males and visual loss tends to be painless and subacute, typically involving both optic nerves. MS lesions in the vestibulocerebellum, brainstem, thalamus and basal ganglia may lead to abnormalities of gaze, saccades, pursuit and nystagmus which can be identified on eye examination. Medial longitudinal fasciculus lesions can cause another frequent presentation of MS, internuclear ophthalmoplegia, with failure of ipsilateral eye adduction and contralateral eye abduction nystagmus. Treatments for MS include high-dose corticosteroids for acute relapses and disease-modifying medications for relapse prevention. These therapies may also have adverse effects on vision, including central serous retinopathy with corticosteroid therapy and macular oedema with fingolimod.

Evaluation of Retinal Structure and Optic Nerve Function Changes in Multiple Sclerosis: Longitudinal Study with 1-Year Follow-Up

Background

Multiple sclerosis (MS) is an autoimmune disease characterized by inflammation and demyelination of the central nervous system which often involves the optic nerve even though only 20% of the patients experience optic neuritis (ON).

Objective

This study aims to compare the retinal structure and optic nerve function between patients with MS and healthy controls (HCs), evaluate optic nerve alterations in MS over 1-year follow-up, and analyze its correlations with disease duration, number of relapses, degree of disability, and different subtypes.

Methods

This is a prospective cohort study involving 58 eyes of MS patients. Optic nerve function was evaluated with best-corrected visual acuity (BCVA), contrast sensitivity, and P100 latency, while the retinal structure was evaluated from the GCIPL and RNFL thickness measured with optical coherence tomography (OCT) and fundus photography.

Results

The MS group had lower BCVA (p=0.001), contrast sensitivity (p < 0.001), mean GCIPL thickness (p < 0.001), and mean RNFL thickness (p < 0.001) than HC. At 6 and 12 months of observations, GCIPL and RNFL (nasal quadrant) of MS patients decreased significantly (p=0.007 and p=0.004, respectively). Disease duration and the number of relapses correlated with delayed P100 latency (r = −0.61, p < 0.001 and r = −0.46, p=0.02). GCIPL and RNFL in the SPMS subtype were thinner than in RRMS.

Conclusions

The retinal structure and optic nerve function of MS patients are worse than those of normal individuals. GCIPL and RNFL thinning occurs at 6 and 12 months but do not correlate with disease duration, the number of relapses, and degree of disability.

Effect of fingolimod vs interferon treatment on OCT measurements and cognitive function in RRMS

OBJECTIVE

To explore prospectively through OCT the rate of retinal layer changes in relapsing-remitting multiple sclerosis patients followed up on fingolimod or interferon, as well as the treatments' differential effects on cognitive tests scores.

METHODS

This prospective observational study enrolled 128 stable RRMS patients treated either with fingolimod (n = 71) or interferon (n = 56). Symbol-Digit Modality Test and retinal OCT scans were obtained at baseline and every 6 to 12 months. A subgroup of patients underwent expanded cognitive tests annually (Brief visual-spatial memory-total recall, BVMT-delayed recall, and Montreal Cognitive Assessment). Retinal-OCT scans were also obtained from 22 age- and sex-matched healthy controls. Mixed effects regression was used to study annualized changes in retinal layers and cognitive function, including differences between treatment groups. Correlations between annualized changes in retinal measurements and cognitive scores were also explored.

RESULTS

Fingolimod treated patients showed no significant difference in the rate of thinning of all retinal layers when compared to healthy controls and had significantly less GCIPL thinning when compared to interferons. SDMT scores improved similarly among both RRMS treatment groups. However, interferon but not fingolimod treated patients had significant decline in MOCA and total recall scores. We also found correlations between the annualized change in GCIPL thickness and annualized change in MOCA scores, and similar correlations with annualized change in total recall scores.

CONCLUSION

Fingolimod has a potential role in reducing retinal neurodegeneration in RRMS. Longitudinal OCT measures appear to be sensitive to changes in cognitive function and may be useful for monitoring neuroprotective therapies.

Optical coherence tomography: a window to the optic nerve in clinically isolated syndrome

In this study, we aimed to evaluate the association of asymptomatic optic nerve demyelinating lesion in patients presenting a clinically isolated syndrome with the asymptomatic retinal neuro-axonal loss previously reported at clinically isolated syndrome. We prospectively recruited 66 patients presenting a clinically isolated syndrome and 66 healthy control subjects matched according to age and gender. All patients underwent brain magnetic resonance imaging including 3D-double inversion recovery (DIR) sequence, optical coherence tomography examination and visual function evaluation, at 2.5-4.5 months after CIS. Evaluation criteria were presence and length of optic nerve DIR hypersignal, retinal layers (including ganglion cell inner plexiform layer and inner nuclear layer) thickness/volume, and low contrast monocular vision acuity (number of letters correctly identified). All clinically isolated syndrome eyes with past history of optic neuritis (CIS-ON) presented an optic nerve DIR hypersignal. We observed asymptomatic optic nerve DIR hypersignal in 22.2% of clinically isolated syndrome eyes without optic neuritis (CIS-NON). In comparison with healthy control, GCIPL volume (in mm3) was significantly lower in CIS-ON eyes [β (95% confidence interval, CI) = -0.121 (-0.168 to -0.074); P < 0.0001], and to a lesser extent in CIS-NON [β (95% CI) = -0.023 (-0.039 to -0.008); P = 0.004]. In comparison to healthy controls, eyes with asymptomatic optic nerve DIR hypersignal presented significantly lower macular ganglion cell inner plexiform layer volume [β (95% CI) = -0.043 (-0.068 to -0.019); P = 0.001], and eyes without did not [β (95% CI) = -0.016 (-0.034 to 0.003); P = 0.083]. Among CIS-NON, macular ganglion cell inner plexiform layer volume decrease was associated with asymptomatic optic nerve DIR hypersignal independently of optic radiations T2 lesions and primary visual cortex volumes (P = 0.012). Symptomatic optic nerve DIR hypersignal were significantly longer (13.8 ± 6.7 mm) than asymptomatic optic nerve hypersignal (10.0 ± 5.5 mm; P = 0.047). Length of optic nerve DIR hypersignal was significantly associated with thinner inner retinal layers (P ≤ 0.001), thicker inner nuclear layer (P = 0.017) and lower low contrast monocular vision acuity (P < 0.05). Compared to healthy control, low contrast monocular vision acuity was significantly lower in CIS-ON eyes (P < 0.0001) and CIS-NON eyes with (P = 0.03) or without asymptomatic optic nerve DIR hypersignal (P = 0.0005). Asymptomatic demyelinating optic nerve DIR hypersignal at the earliest clinical stage of multiple sclerosis is frequent and associated with asymptomatic retinal neuro-axonal loss reported at clinically isolated syndrome stage. Length of optic nerve DIR hypersignal is a biomarker of retinal neuro-axonal loss and visual disability at clinically isolated syndrome stage. Visual disability of clinically isolated syndrome eyes without clinical and subclinical optic nerve involvement might be due to missed optic nerve lesions on MRI. At the earliest clinical stage of multiple sclerosis, our results support considering optical coherence tomography as a window to the optic nerve rather than to the brain.

Spinal cord and infratentorial lesions in radiologically isolated syndrome are associated with decreased retinal ganglion cell/inner plexiform layer thickness

BACKGROUND

The role of retinal imaging with optical coherence tomography (OCT) in assessing individuals with radiologically isolated syndrome (RIS) remains largely unexplored.

OBJECTIVE

To assess retinal layer thicknesses in RIS and examine their associations with clinical features suggestive of increased risk for conversion to multiple sclerosis (MS).

METHODS

A total of 30 RIS subjects and 60 age- and sex-matched healthy controls (HC) underwent retinal imaging with spectral-domain OCT, followed by automated segmentation of retinal layers.

RESULTS

Overall, retinal layer thicknesses did not differ between RIS and HC. However, RIS subjects with spinal cord (SC) lesions had lower ganglion cell + inner plexiform layer (GCIP) thickness compared to HC (-4.41 μm; p = 0.007) and RIS without SC lesions (-3.53 μm; p = 0.041). Similarly, RIS subjects with infratentorial (IT) brain lesions had lower GCIP thickness compared to HC (-4.07 μm; p < 0.001) and RIS without IT lesions (-3.49 μm; p = 0.029). Multivariate analyses revealed that the presence of SC or IT lesions were independently associated with lower GCIP thickness in RIS (p = 0.04 and p = 0.03, respectively). Other patient characteristics, including sex, abnormal cerebrospinal fluid, and presence of gadolinium-enhancing or juxtacortical lesions, were not associated with retinal layer thicknesses.

CONCLUSION

The presence of SC or IT lesions in RIS may be associated with retinal neuro-axonal loss, supporting the presence of more disseminated disease.

Progression of retinal ganglion cell loss in multiple sclerosis is associated with new lesions in the optic radiations

BACKGROUND AND PURPOSE

The mechanism of retinal ganglion cell and retinal nerve fiber layer loss in multiple sclerosis (MS) remains unknown. This study aimed to investigate the association between temporal retinal nerve fiber layer (tRNFL) thinning and disease activity in the brain determined by T2 lesions on magnetic resonance imaging (MRI).

METHODS

Fifty-five consecutive patients with relapsing-remitting MS and 25 controls were enrolled. All patients underwent annual optical coherence tomography and high-resolution MRI scans for tRNFL thickness and brain lesion volume analysis, respectively.

RESULTS

Significant tRNFL thickness reduction was observed over the 3-year follow-up period at a relatively constant rate (1.02 μm/year). Thinning of tRNFL fibers was more prominent in younger patients (P = 0.01). The tRNFL loss was associated with new MRI lesions in the optic radiations (ORs). There was significantly greater tRNFL thinning in patients with new lesional activity in the ORs compared with patients with new lesions outside the ORs (P = 0.009).

CONCLUSIONS

This study supports the notion that retrograde transneuronal degeneration caused by OR lesions might play a role in progressive retinal nerve fiber layer loss. In addition, the results of the study also indicate that the disease-related neurodegenerative changes in the retina start much earlier than the clinical diagnosis of MS.

Adding Papillomacular Bundle Measurements to Standard Optical Coherence Tomography Does Not Increase Sensitivity to Detect Prior Optic Neuritis in Patients with Multiple Sclerosis

Purpose

To improve the detection of retinal nerve fiber layer (RNFL) thinning in multiple sclerosis (MS), a special peripapillary ring scanning algorithm (N-site RNFL, N-RNFL) was developed for spectral domain optical coherence tomography (SD-OCT). In contrast to the standard protocol (ST-RNFL) scanning starts nasally, not temporally, and provides an additional sector of analysis, the papillomacular bundle (PMB). We aimed to ascertain whether the temporal RNFL differs between the two techniques, whether N-RNFL is more sensitive than ST-RNFL to detect previous optic neuritis (ON), and whether analyzing the PMB adds additional sensitivity. Furthermore, we investigated whether RNFL is associated with disease severity and/or disease duration.

Methods

We conducted a cross-sectional case-control study of 38 patients with MS, of whom 24 had a history of ON, and 40 healthy controls (HC). Subjects with ON within the previous 6 months were excluded. Records included clinical characteristics, visual evoked potentials (VEP), and SD-OCT in both techniques.

Results

In a total of 73 evaluable MS eyes, temporal N-RNFL was abnormal in 17.8%, temporal ST-RNFL in 19.2%, and the PMB-RNFL in 21.9%. In ON eyes, the sensitivity of temporal N-RNFL and ST-RNFL did not differ significantly (37.0%/33.3%, p = 0.556). The sensitivity of VEP was 85.2%. RNFL thickness was associated with disease severity in all eyes, with and without a history of ON, and with disease duration.

Conclusion

The two OCT techniques detected previous ON with similar sensitivity, but the sensitivity of VEPs was superior to that of both N-RNFL and ST-RNFL. Our results indicate that the widely used ST-RNFL technique is appropriate for peripapillary RNFL measurements in MS patients.

Optical coherence tomography indicates disease activity prior to clinical onset of central nervous system demyelination

BACKGROUND

Establishing biomarkers for predicting disease activity in demyelinating disease of the central nervous system is crucial for designing appropriate disease modifiying treatment strategies.

OBJECTIVE

To investigate retinal findings and disease activity in patients with radiologically isolated and clinically isolated syndromes.

METHODS

We performed retinal optical coherence tomography and cerebral magnetic resonance imaging in healthy control individuals (n=19), in individuals with non-specific white matter lesions (n=18), and in patients with clinically isolated syndromes (n=18) and radiologically isolated syndromes (n=20).

RESULTS

Reduced volume of retinal nerve fibre layer and increased volume of inner nuclear layer at baseline correlated with subsequent disease activity as measured by an increase in cerebral T2 lesion load in patients with radiologically isolated syndromes. Reduced volume of retinal nerve fibre layer and increased volumes of inner and outer nuclear layer were associated with progression into multiple sclerosis in patients with clinically isolated syndromes.

CONCLUSION

Patients with radiologically and clinically isolated syndromes behave similarly concerning paraclinical disease activity in cerebral magnetic resonance imaging. In both conditions, reduction of retinal nerve fibre layer and increased inner nuclear layer and outer nuclear layer volumes predict disease activity and are associated with progression into multiple sclerosis.

[Optic neuropathy after retrobulbar neuritis in multiple sclerosis: are optical coherence tomography and magnetic resonance imaging useful and necessary follow-up parameters?]

BACKGROUND

This study evaluated whether progressive optic neuropathy (ON) is commonly found after retrobulbar neuritis and whether optical coherence tomography (OCT) is a useful tool for follow-up of patients with multiple sclerosis (MS).

METHODS

An observational study of 86 MS patients (currently treated with immunomodulation) with a past medical history of ON was carried out. Patients were assessed in 2010 and 2012 using the expanded disability status scale (EDSS), visual acuity, visual evoked potentials (VEP) and OCT but magnetic resonance imaging (MRI) was performed only in 2012.

RESULTS

In this study 16 men and 70 women with a mean age of 41.6 and 43.8 years, respectively, were evaluated (28 patients post bilateral and 58 patients post unilateral ON including 114 eyes post-ON and 58 eyes without previous ON). Visual acuity and VEPs improved or remained the same over the study period. Visual acuity, VEPs, retinal nerve fiber layer (RNFL) thickness and macular volume were significantly worse in eyes post-ON compared to eyes without previous ON. The RNFL significantly decreased over the study period in eyes post-ON from an average of 79.9 ± 13.3 μm to 77.0 ± 12.9 μm (p < 0.0001) and eyes without previous ON from 89.5 ± 12.9 μm to 86.0 ± 12.5 μm (p < 0.0001). The number of VEPs and RNFL thickness were significantly correlated with visual acuity in all eyes. In patients after unilateral ON the brain atrophy parameters corpus callosum index (CCI) and cella media index (CMI) were negatively correlated with the EDSS.

CONCLUSION

Initially MS often begins with an episode of ON which can be stabilized by immunomodulation. A mild progressive ON was generally detectable in this study but severe progressive ON was rarely observed. The OCT measurements showed no better correlation than the VEPs with visual acuity; however, OCT can be applied for confirmation of atypical ON. The corpus callosum index seems to be best associated with the degree of disability while, as already described in the literature, the number of T2 lesions is not well correlated with disability, probably due to the small-world network function of the brain and the position of the lesions in areas with no clinical relevance.

Retinal imaging as a source of biomarkers for diagnosis, characterization and prognosis of chronic illness or long-term conditions

The black void behind the pupil was optically impenetrable before the invention of the ophthalmoscope by von Helmholtz over 150 years ago. Advances in retinal imaging and image processing, especially over the past decade, have opened a route to another unexplored landscape, the retinal neurovascular architecture and the retinal ganglion pathways linking to the central nervous system beyond. Exploiting these research opportunities requires multidisciplinary teams to explore the interface sitting at the border between ophthalmology, neurology and computing science. It is from the detail and depth of retinal phenotyping that novel metrics and candidate biomarkers are likely to emerge. Confirmation that in vivo retinal neurovascular measures are predictive of microvascular change in the brain and other organs is likely to be a major area of research activity over the next decade. Unlocking this hidden potential within the retina requires integration of structural and functional data sets, that is, multimodal mapping and longitudinal studies spanning the natural history of the disease process. And with further advances in imaging, it is likely that this area of retinal research will remain active and clinically relevant for many years to come. Accordingly, this review looks at state-of-the-art retinal imaging and its application to diagnosis, characterization and prognosis of chronic illness or long-term conditions.

Evaluation of changes in retinal nerve fiber layer thickness and visual functions in cases of optic neuritis and multiple sclerosis

CONTEXT

Retinal nerve fiber layer (RNFL) thinning has been demonstrated in cases of optic neuritis (ON) and multiple sclerosis (MS) in Caucasian eyes, but no definite RNFL loss pattern or association with visual functions is known in Indian eyes.

AIM

To evaluate RNFL thickness in cases of ON and MS, and to correlate it with visual function changes in Indian patients.

SETTINGS AND DESIGN

Cross-sectional case-control study at a tertiary level institution.

MATERIALS AND METHODS

Cases consisted of patients of (i) typical ON without a recent episode (n = 30:39 ON eyes and 21 fellow eyes), (ii) MS without ON (n = 15;30 eyes) while the controls were age-matched (n = 15; 30 eyes). RNFL thickness was measured using the Stratus 3 °CT. The visual functions tested included the best-corrected visual acuity (BCVA), contrast sensitivity, stereopsis, visual evoked responses, and visual fields.

STATISTICAL ANALYSIS USED

Intergroup analysis was done using ANOVA and Pearson's correlation coefficient used for associations.

RESULTS

RNFL thickness was reduced significantly in the ON and MS patients compared to the controls (P-0.001). Maximum loss is in the temporal quadrant. Lower visual function scores are associated with reduced average overall RNFL thickness. In ON group, RNFL thinning is associated with severe visual field defects while contrast sensitivity has strongest correlation with RNFL in the MS group.

CONCLUSIONS

RNFL thickness is reduced in ON and MS cases in a pattern similar to Caucasians and is associated with the magnitude of impairment of other visual parameters. Contrast sensitivity and stereoacuity are useful tests to identify subclinical optic nerve involvement in multiple sclerosis.

Optical coherence tomography versus visual evoked potential in multiple sclerosis patients

BACKGROUND

Optical coherence tomography (OCT) is a non-invasive instrument, which can be used to estimate the thickness of the retinal nerve fibre layer (RNFL) and provides an indirect measurement of axonal destruction in multiple sclerosis (MS). The main aim of this study was to find out any correlations between P100 latency in visual evoked potential (VEP) and RNFL thickness.

METHODS

The patients with the definite history of optic neuritis regardless of the diagnosis of MS were included. The eyes with the history of blurred vision and increased VEP latency (> 115 milliseconds) were considered as cases and the eyes with normal latency were regarded as controls. RNFL thickness was compared between two groups of cases and controls. In addition, the correlation between VEP P100 latency and RNFL thickness in four quadrants of superior, nasal, inferior and temporal fields was estimated by spearman correlation coefficient. RNFL thickness between the patients with history of clinically isolated syndrome (CIS) was also compared to other two subgroups of RRMS and SPMS.

RESULTS

There was significant negative correlation between VEP P100 latency and RNFL. In all four quadrants, with increasing VEP latency, RNFL thickness decreased. Furthermore, there was significant correlation between P100 latencies and mean RNFL thickness [Pearson correlation coefficient = -0.527, P < 0.001; RNFL (mean) = (-0.44 ± 0.087) × P100 + (153.6 ± 10.94)]. Comparing RNFL thickness between three groups of CIS, RRMS, and SPSM, no significant difference was detected in RNFL thickness (P > 0.05). Power analysis demonstrated that RNFL average had the highest area under curve.

CONCLUSION

OCT does have good correlations with P100 latency, indicating retinal non-myelinated axonal involvement in early stages in addition to the myelinated axonal involvement. However, it cannot be used as the sole test in evaluating visual pathway in optic neuritis and complementary tests as VEPs are recommended.