Microcystic macular oedema, thickness of the inner nuclear layer of the retina, and disease characteristics in multiple sclerosis: a retrospective study

Pediatric optic neuritis

PURPOSE OF REVIEW

Pediatric optic neuritis may be challenging to diagnose and treat. Significant clinical investigation of optic neuritis occurring in adults guides current clinical practices. Differences in presentation and prognosis exist for pediatric patients with optic neuritis when compared with adults including the risk of developing multiple sclerosis. The aim of this review is to provide an update on latest advances in the diagnosis, treatment and current research concerning pediatric optic neuritis.

RECENT FINDINGS

Limited case series and retrospective reviews constitute much of the data we know about patients with pediatric optic neuritis. Pediatric optic neuritis is included in the spectrum of neuroinflammatory diseases. Testing modalities (ocular coherence tomography and visual evoked potentials) and serologic testing (antibodies against aquaporin-4 and myelin oligodendrocyte glycoprotein) are being investigated for diagnostic and prognostic value. The low incidence of pediatric optic neuritis results in small sample sizes may contribute to conflicting results of different studies.

SUMMARY

Recent advances in diagnostic and serologic testing in pediatric neuritis may offer better diagnosis, treatment and prediction of prognosis. Validation requires well designed prospective research.

OPTICAL COHERENCE TOMOGRAPHY ANALYSIS OF OUTER RETINAL TUBULATIONS: Sequential Evolution and Pathophysiological Insights

PURPOSE

To describe the sequential evolution of outer retinal tubulations (ORTs) in patients diagnosed with choroidal neovascularization and/or retinal pigment epithelium atrophy.

METHODS

Retrospective evaluation of spectral domain optical coherence tomography of a consecutive cohort of patients with various retinal conditions.

RESULTS

We reviewed the clinical findings of 238 eyes of 119 consecutive patients (54 men and 65 women) with a mean age of 76.2 ± 14.2 years (range: 57-90) and a mean follow-up of 3 ± 1.6 years (range 1-7). Over the follow-up period, ORTs were diagnosed in 67 of 238 eyes (28.1%), 9 of which were imaged with sequential, eye-tracked spectral domain optical coherence tomography dating from the beginning of ORT formation. The presence of geographic atrophy and subretinal hyperreflective material at baseline were found to be risk factors for ORT development (P < 0.001 and P < 0.001, respectively). Outer retinal tubulations were divided into forming versus formed morphologies. The latter was comprised open and closed ORTs of which the open subtype was the most common. The formation of ORTs was significantly associated with microcystic macular lesions in the inner nuclear layer and the downward displacement of the outer plexiform layer, referred to as the outer plexiform layer subsidence sign (P < 0.001).

CONCLUSION

Outer retinal tubulation is a frequent optical coherence tomography finding in eyes with choroidal neovascularization and geographic atrophy. Open ORTs with progressive scrolled edges and shortened diameter were significantly associated with microcystic macular lesions in the inner nuclear layer and the outer plexiform layer subsidence sign.

Retinal imaging with optical coherence tomography: a biomarker in multiple sclerosis?

Multiple sclerosis (MS) is a progressive neurological disorder characterized by both inflammatory and degenerative components that affect genetically susceptible individuals. Currently, the cause of MS remains unclear, and there is no known cure. Commonly used therapies tend to target inflammatory aspects of MS, but may not halt disease progression, which may be governed by the slow, subclinical accumulation of injury to neuroaxonal structures in the central nervous system (CNS). A recognized challenge in the field of MS relates to the need for better methods of detecting, quantifying, and ameliorating the effects of subclinical disease. Simply stated, better biomarkers are required. To this end, optical coherence tomography (OCT) provides highly reliable, reproducible measures of axonal damage and neuronal loss in MS patients. OCT-detected decrements in retinal nerve fiber layer thickness and ganglion-cell layer-inner plexiform layer thickness, which represent markers of axonal damage and neuronal injury, respectively, have been shown to correlate with worse visual outcomes, increased clinical disability, and magnetic resonance imaging-measured burden of disease in MS patients. Recent reports have also suggested that OCT-measured microcystic macular edema and associated thickening of the retinal inner nuclear layer represent markers of active CNS inflammatory activity. Using the visual system as a putative clinical model in MS, OCT measures of neuroaxonal structure can be correlated with functional outcomes to help us elucidate mechanisms of CNS injury and repair. In this review, we evaluate evidence from the published literature and ongoing clinical trials that support the emerging role of OCT in diagnosing, staging, and determining response to therapy in MS patients.

MOG-IgG-associated disease has a stereotypical clinical course, asymptomatic visual impairment and good treatment response

Objectives

We investigated the clinical characteristics and treatment response in myelin oligodendrocyte glycoprotein antibody (MOG-IgG)-associated disease and looked for evidence of subclinical disease.

Methods

We prospectively evaluated the frequency and pattern of relapse, tested afferent visual function and monitored treatment response in 42 south Asian patients from a single centre.

Results

Eighteen patients (42.9%) had monophasic and 24 (57.1%) a relapsing course. Disease duration was longer (P<0.02) in those with a relapsing course. Median time to the second attack was prolonged (P<0.04) in patients with recurrent transverse myelitis when compared with neuromyelitis optica spectrum disorder and recurrent optic neuritis. Thirteen out of 17 patients (76.5%) initially presenting with optic neuritis developed recurrent optic neuritis later. After the first attack of transverse myelitis, 17 out of 22 (77.3%) had disease confined to the spinal cord. Optical coherence tomography detected peripapillary retinal nerve fibre layer thickness (P<0.05) and macular ganglion cell complex volume (P<0.005) abnormalities in seven out of 10 (70.0%) patients without clinical optic neuritis. Immunosuppressants induced remission in 17 out of 22 (77.3%) patients during a median follow-up of 48 months and the median Expanded Disability Status Score was 1 (range 1–10).

Conclusion

Our study highlighted the tendency for stereotypical attacks in MOG-IgG-associated disease, heterogeneity in clinical course among subtypes, subclinical visual impairment and the need for early and sustained immunosuppressive therapy.

Normal Variation of Photoreceptor Outer Segment Volume With Age, Gender, Refractive Error, and Vitreomacular Adhesion

BACKGROUND AND OBJECTIVE

Thickness and volume changes of the photoreceptor outer segment (PROS) layer on spectral-domain optical coherence tomography (SD-OCT) images are associated with various disease states. However, there are limited data on normal anatomical variation. This study evaluates the correlation of PROS volume with age, gender, refractive error, and presence of vitreomacular adhesion (VMA) in healthy subjects.

PATIENTS AND METHODS

SD-OCT scans of 68 normal eyes were analyzed. The ellipsoid zone and the apical retinal pigment epithelium boundary were segmented using an automated algorithm. The PROS volume was calculated as the region bounded by these two layers within a 6-mm diameter circle centered at the fovea. A general linear model was used for statistical analysis.

RESULTS

PROS volume increased with age to a significant degree (P = .013). Gender, refractive error, and presence of VMA were insignificant factors.

CONCLUSION

PROS volume, as measured on routine SD-OCT, increases with age in healthy subjects, after adjusting for gender, refractive error, and VMA. [Ophthalmic Surg Lasers Imaging Retina. 2018;49:523-527.].

Microcystic macular oedema in optic neuropathy: case series and literature review

Cavitations in the inner nuclear layer associated with severe optic atrophy and loss of retinal ganglion cells have clinically been termed microcystic macular oedema (MME). We describe a case series of MME in patients of all ages but predominantly younger patients with a wide range of optic atrophies ranging from acute onset optic disc drusen associated ischemic optic neuropathy to slowly progressive disease as glaucoma. There were no physical distinctions between MME in different causes of optic atrophy suggesting a common causative mechanism. We reviewed the literature on MME and it appears that MME is associated with more severe visual loss, and is more common in hereditary optic neuropathies and neuromyelitis optica spectrum disease rather than in patients with optic atrophy secondary to multiple sclerosis and glaucoma. Three main causative mechanisms have been proposed, including increased vitreal traction on the macular as the ganglion cells are lost. Others have suggested that trans-synaptic loss of cells in the inner nuclear layer causes formation of empty spaces or cavities. Finally, some have hypothesized a disturbance in the fluid homeostasis of the inner retina as Müller cells are lost or their function is impaired. There are no known treatments of MME. In conclusion, MME seems to be a marker of severe optic nerve atrophy irrespective of the underlying cause.

Using the Anterior Visual System to Assess Neuroprotection and Remyelination in Multiple Sclerosis Trials

PURPOSE OF REVIEW

Clinical trials using agents directed at neuroprotection and remyelination in multiple sclerosis (MS) are needed. As optic neuritis (ON) is common in people with MS and the pathology of ON is similar to other MS lesions in the brain, measurements of the anterior visual system are frequently utilized in neuroprotection and remyelination trials. Understanding the strengths and weaknesses of the measurements is vital when interpreting the results of this research.

RECENT FINDINGS

Techniques such as visual evoked potentials (VEP) and optical coherence tomography (OCT) are well established in MS and are thought to measure axonal integrity and myelination. Novel imaging techniques can also be used in conjunction with these measurements to provide better insight into optic nerve structure and function. Magnetization transfer imaging (MTR) together with optic nerve area and volume measures neurodegeneration; diffusion tensor imaging (DTI) measures myelination status and neurodegeneration. However, these techniques require various levels of experience to interpret, and all can be confounded by ocular motion and surrounding fat and bone. This article provides a review of established and novel techniques to measure the anterior visual system in multiple sclerosis with a focus on the evidence to support their use as outcome measures in clinical trials focused on neuroprotection and remyelination therapies.

Multi-layer Fast Level Set Segmentation for Macular OCT

Segmenting optical coherence tomography (OCT) images of the retina is important in the diagnosis, staging, and tracking of ophthalmological diseases. Whereas automatic segmentation methods are typically much faster than manual segmentation, they may still take several minutes to segment a three-dimensional macular scan, and this can be prohibitive for routine clinical application. In this paper, we propose a fast, multi-layer macular OCT segmentation method based on a fast level set method. In our framework, the boundary evolution operations are computationally fast, are specific to each boundary between retinal layers, guarantee proper layer ordering, and avoid level set computation during evolution. Subvoxel resolution is achieved by reconstructing the level set functions after convergence. Experiments demonstrate that our method reduces the computation expense by 90% compared to graph-based methods and produces comparable accuracy to both graph-based and level set retinal OCT segmentation methods.

Multicenter reliability of semiautomatic retinal layer segmentation using OCT

Objective

To evaluate the inter-rater reliability of semiautomated segmentation of spectral domain optical coherence tomography (OCT) macular volume scans.

Methods

Macular OCT volume scans of left eyes from 17 subjects (8 patients with MS and 9 healthy controls) were automatically segmented by Heidelberg Eye Explorer (v1.9.3.0) beta-software (Spectralis Viewing Module v6.0.0.7), followed by manual correction by 5 experienced operators from 5 different academic centers. The mean thicknesses within a 6-mm area around the fovea were computed for the retinal nerve fiber layer, ganglion cell layer (GCL), inner plexiform layer (IPL), inner nuclear layer, outer plexiform layer (OPL), and outer nuclear layer (ONL). Intraclass correlation coefficients (ICCs) were calculated for mean layer thickness values. Spatial distribution of ICC values for the segmented volume scans was investigated using heat maps.

Results

Agreement between raters was good (ICC > 0.84) for all retinal layers, particularly inner retinal layers showed excellent agreement across raters (ICC > 0.96). Spatial distribution of ICC showed highest values in the perimacular area, whereas the ICCs were poorer for the foveola and the more peripheral macular area. The automated segmentation of the OPL and ONL required the most correction and showed the least agreement, whereas differences were less prominent for the remaining layers.

Conclusions

Automated segmentation with manual correction of macular OCT scans is highly reliable when performed by experienced raters and can thus be applied in multicenter settings. Reliability can be improved by restricting analysis to the perimacular area and compound segmentation of GCL and IPL.

Acetazolamide Reduces Retinal Inner Nuclear Layer Thickness in Microcystic Macular Edema Secondary to Optic Neuropathy

Optic neuropathy (ON) is commonly complicated by microcystic macular edema (MME), that is, small vertical cystoid spaces in the inner nuclear layer (INL) of the macula. We performed a retrospective consecutive case series of 14 eyes from 11 patients with ON and MME that were treated with oral acetazolamide, acting on cellular water transport. Contralateral eyes without MME were used as controls. Segmentation of images obtained with OCT was used to determine changes of individual retinal layer thickness during treatment. Retinal INL thickness consistently decreased in all eyes after 2–3 weeks of treatment. Recurrence of MME was observed after treatment cessation. No significant change of retinal thickness was found in contralateral unaffected eyes. Visual function did not change with treatment. Acetazolamide significantly improved the MME in eyes with ON. However, visual function did not. Acetazolamide is a treatment option for MME associated with ON but without an impact on the visual function.

Optical coherence tomography in neuromyelitis optica spectrum disorders: potential advantages for individualized monitoring of progression and therapy

Neuromyelitis optica spectrum disorders (NMOSD) are mostly relapsing inflammatory disorders of the central nervous system (CNS). Optic neuritis (ON) is the first NMOSD-related clinical event in 55% of the patients, which causes damage to the optic nerve and leads to visual impairment. Retinal optical coherence tomography (OCT) has emerged as a promising method for diagnosis of NMOSD and potential individual monitoring of disease course and severity. OCT not only detects damage to the afferent visual system caused by ON but potentially also NMOSD-specific intraretinal pathology, i.e. astrocytopathy. This article summarizes retinal involvement in NMOSD and reviews OCT methods that could be used now and in the future, for differential diagnosis, for monitoring of disease course, and in clinical trials.

Predictors of retinal atrophy in multiple sclerosis: A longitudinal study using spectral domain optical coherence tomography with segmentation analysis

BACKGROUND

Multiple sclerosis is an inflammatory demyelinating disease characterized by progressive axonal loss affecting mainly the inner retinal layers. Optical coherence tomography (OCT) provides in-vivo quantification of the retinal layers and allows measuring progressive retinal changes. Our objective was to assess the longitudinal changes in the retina using spectral domain OCT (SDOCT) and to identify independent predictors affecting retinal thinning in MS patients.

METHODS

A prospective study in a tertiary care MS center was conducted to study the longitudinal retinal changes in MS patients. All subjects underwent baseline and follow up OCT assessment with segmentation analysis. Regression analysis was performed to assess clinical factors (age, sex, disease duration, history of optic neuritis before baseline, non-ocular clinical relapses) and MRI disease activity during the follow-up period.

RESULTS

The study included 102 MS patients with a mean follow-up duration of 3.9 ± SD years. At the last follow-up assessments, there were significant thinning of the average macular thickness (AMT) (p < .001), macular nerve fiber layer (MRNFL) (p < .001), ganglion cell-inner plexiform layer (GCIPL) (p < .001), and the peripapillary nerve fiber layer (PRNFL) (p < .001), compared to baseline. Early disease duration up to 10 years was associated with thinning of AMT, PRNFL, and GCIPL, while longer disease duration (> 15 years) was associated with only GCIPL thinning. Prior optic neuritis was predictive of more thinning of PRNFL (p = < .01), while MRI activity and female gender were significantly associated with more MRNFL thinning (p = < .01).

CONCLUSION

MS is associated with longitudinal thinning affecting AMT inner retinal layers (MRNFL, GCIPL, PRNFL). Early disease duration, female gender, MRI activity, and prior optic neuritis were predictive of faster rate of neuro-axonal loss. This may have implications in the design of future therapeutic trials.

The clinical perspective: How to personalise treatment in MS and how may biomarkers including imaging contribute to this?

BACKGROUND

Multiple sclerosis (MS) is a highly heterogeneous disease, both in its course and in its response to treatments. Effective biomarkers may help predict disability progression and monitor patients' treatment responses.

OBJECTIVE

The aim of this review was to focus on how biomarkers may contribute to treatment individualisation in MS patients.

METHODS

This review reflects the content of presentations, polling results and discussions on the clinical perspective of MS during the first and second Pan-European MS Multi-stakeholder Colloquia in Brussels in May 2014 and 2015.

RESULTS

In clinical practice, magnetic resonance imaging (MRI) measures play a significant role in the diagnosis and follow-up of MS patients. Together with clinical markers, the rate of MRI-visible lesion accrual once a patient has started treatment may also help to predict subsequent treatment responsiveness. In addition, several molecular (immunological, genetic) biomarkers have been established that may play a role in predictive models of MS relapses and progression. To reach personalised treatment decisions, estimates of disability progression and likely treatment response should be carefully considered alongside the risk of serious adverse events, together with the patient's treatment expectations.

CONCLUSION

Although biomarkers may be very useful for individualised decision making in MS, many are still research tools and need to be validated before implementation in clinical practice.

Morphological and Functional Inner and Outer Retinal Layer Abnormalities in Eyes with Permanent Temporal Hemianopia from Chiasmal Compression

Purpose

The aims of this study are to compare optical coherence tomography (OCT)-measured macular retinal layers in eyes with permanent temporal hemianopia from chiasmal compression and control eyes; to compare regular and slow-flash multifocal electroretinography (mfERG) in patients and controls; and to assess the correlation between OCT, mfERG, and central visual field (SAP) data.

Methods

Forty-three eyes of 30 patients with permanent temporal hemianopia due to pituitary tumors who were previously submitted to chiasm decompression and 37 healthy eyes of 19 controls were submitted to macular spectral domain OCT, mfERG, and 10-2 SAP testing. After segmentation, the thickness of the macular retinal nerve fiber layer (RNFL), ganglion cell layer (GCL), inner plexiform layer (IPL), inner nuclear layer (INL), outer plexiform layer (OPL), outer nuclear layer, and photoreceptor layer (PRL) was measured. Amplitudes and oscillatory potentials (OPs) were measured on regular and slow-flash mfERG, respectively, and expressed as the mean values per quadrant and hemifield.

Results

RNFL, GCL, and IPL thickness measurements were significantly reduced in all quadrants, whereas INL, OPL, and PRL thicknesses were significantly increased in the nasal quadrants in patients compared to those in controls. Significant correlations between OCT and 10-2 SAP measurements were positive for the RNFL, GCL, and IPL and negative for the INL, OPL, and PRL. OPs and mfERG N1 amplitudes were significantly reduced in the nasal hemiretina of patients. Significant correlations were found between OP and mfERG amplitudes for inner and outer nasal hemiretina OCT measurements, respectively.

Conclusion

Patients with permanent temporal hemianopia from previously treated chiasmal compression demonstrated significant thinning of the RNFL, GCL, IPL, and thickening of the INL, OPL, and PRL associated with reduced OP and mfERG N1 amplitudes, suggesting that axonal injury to the inner retina leads to secondary damage to the outer retina in this condition.

Optical coherence tomography in diagnosis and monitoring multiple sclerosis

This paper presents application of optical coherence tomography (OCT) for diagnosis and monitoring of multiple sclerosis (MS). The peripapillary retinal nerve fibre layer thinning and the reduced total macular volume analysis are shown. With the course of the MS, the severity of these abnormalities increases which reflects the progressive degeneration of retinal ganglion cells and nerve fibres. The OCT parameters are sensitive, non-invasive indicators useful in assessing the progression of inflammation and neurodegeneration in MS.

Retinal layer segmentation in multiple sclerosis: a systematic review and meta-analysis

BACKGROUND

Structural retinal imaging biomarkers are important for early recognition and monitoring of inflammation and neurodegeneration in multiple sclerosis. With the introduction of spectral domain optical coherence tomography (SD-OCT), supervised automated segmentation of individual retinal layers is possible. We aimed to investigate which retinal layers show atrophy associated with neurodegeneration in multiple sclerosis when measured with SD-OCT.

METHODS

In this systematic review and meta-analysis, we searched for studies in which SD-OCT was used to look at the retina in people with multiple sclerosis with or without optic neuritis in PubMed, Web of Science, and Google Scholar between Nov 22, 1991, and April 19, 2016. Data were taken from cross-sectional cohorts and from one timepoint from longitudinal studies (at least 3 months after onset in studies of optic neuritis). We classified data on eyes into healthy controls, multiple-sclerosis-associated optic neuritis (MSON), and multiple sclerosis without optic neuritis (MSNON). We assessed thickness of the retinal layers and we rated individual layer segmentation performance by random effects meta-analysis for MSON eyes versus control eyes, MSNON eyes versus control eyes, and MSNON eyes versus MSON eyes. We excluded relevant sources of bias by funnel plots.

FINDINGS

Of 25 497 records identified, 110 articles were eligible and 40 reported data (in total 5776 eyes from patients with multiple sclerosis [1667 MSON eyes and 4109 MSNON eyes] and 1697 eyes from healthy controls) that met published OCT quality control criteria and were suitable for meta-analysis. Compared with control eyes, the peripapillary retinal nerve fibre layer (RNFL) showed thinning in MSON eyes (mean difference -20·10 μm, 95% CI -22·76 to -17·44; p<0·0001) and in MSNON eyes (-7·41 μm, -8·98 to -5·83; p<0·0001). The macula showed RNFL thinning of -6·18 μm (-8·07 to -4·28; p<0·0001) in MSON eyes and -2·15 μm (-3·15 to -1·15; p<0·0001) in MSNON eyes compared with control eyes. Atrophy of the macular ganglion cell layer and inner plexiform layer (GCIPL) was -16·42 μm (-19·23 to -13·60; p<0·0001) for MSON eyes and -6·31 μm (-7·75 to -4·87; p<0·0001) for MSNON eyes compared with control eyes. A small degree of inner nuclear layer (INL) thickening occurred in MSON eyes compared with control eyes (0·77 μm, 0·25 to 1·28; p=0·003). We found no statistical difference in the thickness of the combined outer nuclear layer and outer plexiform layer when we compared MSNON or MSON eyes with control eyes, but we found a small degree of thickening of the combined layer when we compared MSON eyes with MSNON eyes (1·21 μm, 0·24 to 2·19; p=0·01).

INTERPRETATION

The largest and most robust differences between the eyes of people with multiple sclerosis and control eyes were found in the peripapillary RNFL and macular GCIPL. Inflammatory disease activity might be captured by the INL. Because of the consistency, robustness, and large effect size, we recommend inclusion of the peripapillary RNFL and macular GCIPL for diagnosis, monitoring, and research.

FUNDING

None.

Microcystoid Macular Changes in Association With Idiopathic Epiretinal Membranes in Eyes With and Without Glaucoma: Clinical Insights

PURPOSE

To describe the clinical and surgical significance of microcystoid macular changes in the inner nuclear layer in patients with idiopathic epiretinal membranes, with and without glaucomatous optic neuropathy.

DESIGN

Retrospective case series.

METHODS

Clinical charts and spectral-domain optical coherence tomography images of 264 eyes of 234 consecutive patients diagnosed with idiopathic epiretinal membranes were reviewed and analyzed. Surgical data were analyzed in a subgroup of eyes with microcystoid macular changes treated with pars plana vitrectomy and epiretinal and internal limiting membrane peel. In surgical cases, postoperative functional and anatomic results at 1 and 6 months were compared between glaucomatous and nonglaucomatous eyes. Associations of microcystoid macular changes with visual acuity and other morphometric parameters were assessed by means of linear or multiple logistic regressions.

RESULTS

Microcystoid macular changes in the inner nuclear layer were diagnosed in 52 out of 264 eyes with epiretinal membranes (19.7%), of which 28 (55.0%) had concomitant glaucoma. The likelihood to develop microcystoid macular changes increased at advanced glaucoma and epiretinal membrane stages. The morphology of microcystoid macular changes was similar between glaucomatous and nonglaucomatous eyes. Forty-four out of 52 eyes (84.6%) with microcystoid macular changes, of which 20 were with glaucoma and 24 without glaucoma, underwent surgery with pars plana vitrectomy and epiretinal and internal limiting membrane peel. At 1 and 6 months after surgery the mean number of microcysts decreased significantly from baseline in nonglaucomatous eyes (P = .003 and P = .002, respectively) and remained unchanged in glaucomatous eyes (P = .400 and P = .700, respectively).

CONCLUSIONS

This study reports a high frequency of microcystoid macular changes in the inner nuclear layer in eyes with concomitant epiretinal membrane and glaucomatous optic neuropathy. In glaucomatous eyes, pars plana vitrectomy with epiretinal and internal limiting membrane peel was ineffective in the treatment of microcystoid macular changes.

Association of Retinal Architecture, Intrathecal Immunity, and Clinical Course in Multiple Sclerosis

Importance

Biomarkers to estimate long-term outcomes in patients with multiple sclerosis (MS) and to assign patients to individual treatment regimens are urgently needed.

Objective

To assess whether retinal layer volumes are correlated with immune cell subsets and immunoglobulin indices in the cerebrospinal fluid and whether retinal layer volumes alone or in combination with intrathecal variables are associated with worsening of disease in patients with relapsing-remitting MS.

Design, Setting, and Participants

This observational cohort study included 312 patients with relapsing-remitting MS in 2 independent cohorts (72 patients with short disease duration [cohort 1] and 240 patients with longer disease duration [cohort 2]) treated at a single German university hospital from April 15, 2013, through November 11, 2015.

Main Outcomes and Measures

The common ganglion cell and inner plexiform layer (GCIPL) and inner nuclear layer (INL) volumes were tested for association with the immunoglobulin indices and the frequencies of immune cells in the cerebrospinal fluid (including B cells, T cells, and natural killer cells) (cohort 1). Volumes of GCIPL alone (cohorts 1 and 2) or GCIPL corrected for intrathecal B-cell frequencies (cohort 1) were tested for their association with worsening disability.

Results

A total of 312 patients (212 women [67.9%] and 100 men [32.1%]; median age, 34.0 years [interquartile range (IQR), 28.0-42.0 years]) were available for analysis. In cohort 1 (50 women [69.4%] and 22 men [30.6%]; median age, 31.0 years [IQR, 26.3-38.3 years]), with short disease durations (median, 1.0 months [IQR, 1.0-2.0 months]), low GCIPL volumes were associated with increased intrathecal B-cell frequencies (median, 1.96% [IQR, 1.45%-4.20%]) and intrathecal IgG synthesis (median cerebrospinal fluid/serum IgG index, 0.78 [IQR, 0.53-1.07]). The INL volumes correlated with the frequencies of intrathecal CD56bright natural killer cells (r = 0.28; P = .007). Individuals with low GCIPL volumes (<1.99 mm3) had a 6.4-fold risk for worsening disability during follow-up compared with patients with higher GCIPL values (95% CI, 1.7-24.2; P = .007). This finding was reproduced in cohort 2 (162 women [67.5%] and 78 men [32.5%]; median age, 34.0 years [IQR, 29.0-42.0 years]) consisting of patients with longer disease durations (median, 36.0 months [IQR, 21.0-60.0 months]) (hazard ratio, 2.4; 95% CI, 1.2-4.8; P = .02). In both cohorts, INL volumes correlated with the prospective increase in T2 lesion load and the number of gadolinium-enhancing lesions.

Conclusions and Relevance

Retinal layers reflect different aspects of disease activity during MS. Loss of GCIPL is associated with intrathecal B-cell immunity and constitutes an independent risk factor for worsening disability, whereas high INL volumes are associated with activity on magnetic resonance imaging in the brain parenchyma. Thus, retinal optical coherence tomography might be a means to support stratification of patients with MS for different therapeutic regimens.

Retinal ganglion cell analysis in multiple sclerosis and optic neuritis: a systematic review and meta-analysis

The aim of this study was to summarise existing findings regarding optical coherence tomography (OCT) measurements of ganglion cell layer (GCL) alterations in optic neuritis (ON) and multiple sclerosis (MS). Peer-reviewed studies published prior to April 2016 were searched using PubMed, EMBASE, Web of Science and Scopus. Studies were included if they measured GCL thickness using OCT in patients with either ON, MS or clinically isolated syndrome. For the meta-analysis, we compared GCL thickness in MS patients with and without prior ON, to healthy controls. 42/252 studies were reviewed. In acute ON, studies showed significant thinning of the GCL within the first 5 weeks (n = 5), earlier than retinal nerve fibre layer (RNFL) thinning. GCL thinning at 1-2 months after acute ON predicted visual function at 6 months (n = 3). The meta-analysis showed that the thickness of the GCL was significantly reduced in MS patients both with and without previous ON compared to healthy controls. GCL thinning was associated with visual function in most studies (n = 10) and expanded disability status scale (EDSS) scores (n = 6). In acute ON, thinning of the GCL is measurable prior to RNFL thinning, and GCL thickness after 1-2 months may predict visual function after 6 months. Furthermore, GCL thinning occurs in MS both with and without prior ON, and may be associated with visual function and EDSS score. This suggests that the GCL is a promising biomarker, which may be used to examine in vivo neurodegeneration in ON and MS.

Automated retinal imaging and trend analysis - a tool for health monitoring

Most current diagnostic devices are expensive, require trained specialists to operate and gather static images with sparse data points. This leads to preventable diseases going undetected until late stage, resulting in greatly narrowed treatment options. This is especially true for retinal imaging. Future solutions are low cost, portable, self-administered by the patient, and capable of providing multiple data points, population analysis, and trending. This enables preventative interventions through mass accessibility, constant monitoring, and predictive modeling.

Retrograde trans-synaptic visual pathway degeneration in multiple sclerosis: A case series

Background:

Trans-synaptic degeneration (TSD) describes the propagation of neuronal injury through synaptic pathways in the human nervous system and may be linked to the accelerated retinal atrophy seen in multiple sclerosis (MS).

Results:

We report six cases where homonymous, hemi-macular ganglion cell + inner plexiform (GCIP) thickness reduction was seen in conjunction with posterior visual pathway lesions. Macular microcystoid changes of the inner nuclear layer (INL) were seen in a subset of three subjects.

Conclusion:

Our findings highlight the utility of assessing regional GCIP changes to identify potential retrograde TSD in MS and demonstrate that INL changes may be an accompaniment in such instances.

Optical coherence tomography segmentation analysis in relapsing remitting versus progressive multiple sclerosis

Introduction

Optical coherence tomography (OCT) with retinal segmentation analysis is a valuable tool in assessing axonal loss and neuro-degeneration in multiple sclerosis (MS) by in-vivo imaging, delineation and quantification of retinal layers. There is evidence of deep retinal involvement in MS beyond the inner retinal layers. The ultra-structural retinal changes in MS in different MS phenotypes can reflect differences in the pathophysiologic mechanisms. There is limited data on the pattern of deeper retinal layer involvement in progressive MS (PMS) versus relapsing remitting MS (RRMS). We have compared the OCT segmentation analysis in patients with relapsing-remitting MS and progressive MS.

Methods

Cross-sectional study of 113 MS patients (226 eyes) (29 PMS, 84 RRMS) and 38 healthy controls (72 eyes). Spectral domain OCT (SDOCT) using the macular cube acquisition protocol (Cirrus HDOCT 5000; Carl Zeiss Meditec) and segmentation of the retinal layers for quantifying the thicknesses of the retinal layers. Segmentation of the retinal layers was carried out utilizing Orion software (Voxeleron, USA) for quantifying the thicknesses of individual retinal layers.

Results

The retinal nerve finer layer (RNFL) (p = 0.023), the ganglion-cell/inner plexiform layer (GCIPL) (p = 0.006) and the outer plexiform layer (OPL) (p = 0.033) were significantly thinner in PMS compared to RRMS. There was significant negative correlation between the outer nuclear layer (ONL) and EDSS (r = -0.554, p = 0.02) in PMS patients. In RRMS patients with prior optic neuritis, the GCIPL correlated negatively (r = -0.317; p = 0.046), while the photoreceptor layer (PR) correlated positively with EDSS (r = 0.478; p = 0.003).

Conclusions

Patients with PMS exhibit more atrophy of both the inner and outer retinal layers than RRMS. The ONL in PMS and the GCIPL and PR in RRMS can serve as potential surrogate of disease burden and progression (EDSS). The specific retinal layer predilection and its correlation with disability may reflect different pathophysiologic mechanisms and various stages of progression in MS.

Disease-modifying therapies modulate retinal atrophy in multiple sclerosis: A retrospective study

OBJECTIVE

To retrospectively investigate whether disease-modifying therapies (DMTs) exert differential effects on rates of retinal atrophy in relapsing-remitting multiple sclerosis (RRMS), as assessed using optical coherence tomography (OCT).

METHODS

A total of 402 patients with RRMS followed at the Johns Hopkins MS Center who underwent Cirrus-HD OCT were assessed for eligibility. Inclusion criteria included at least 1 year of OCT follow-up and adherence to a single DMT during the period of follow-up. Combined thickness of the ganglion cell + inner plexiform (GCIP) and other retinal layers was computed utilizing automated macular segmentation. Retinal thickness changes were analyzed using mixed-effects linear regression.

RESULTS

The effects of glatiramer acetate (GA; n = 48), natalizumab (NAT; n = 46), and interferon-β-1a subcutaneously (IFN_SC; n = 35) and intramuscularly (IFN_IM; n = 28) were assessed. Baseline analyses revealed no significant differences between groups in terms of age, sex, optic neuritis history, or follow-up duration. During follow-up, relative to NAT-treated patients, IFN_SC- and GA-treated patients exhibited 0.37 μm/y (p < 0.001) and 0.14 μm/y (p = 0.035) faster rates of GCIP thinning, respectively, adjusting for the interval between initiation of DMT and OCT monitoring (gap time), age, sex, relapses, and disease duration. In the IFN_SC group, GCIP thinning was 1.53 μm/y faster during the first year of therapy vs during the time interval afterwards (p < 0.001).

CONCLUSIONS

Rates of GCIP atrophy in patients with RRMS vary according to DMT utilization. Our findings support OCT for monitoring neurodegenerative treatment effects in the retina, an easily accessible tissue, and as a practical outcome measure in RRMS clinical trials.

Imaging retina to study dementia and stroke

With increase in life expectancy, the number of persons suffering from common age-related brain diseases, including neurodegenerative (e.g., dementia) and cerebrovascular (e.g., stroke) disease is expected to rise substantially. As current neuro-imaging modalities such as magnetic resonance imaging may not be able to detect subtle subclinical changes (resolution <100-500 μm) in dementia and stroke, there is an urgent need for other complementary techniques to probe the pathophysiology of these diseases. The retina - due to its anatomical, embryological and physiological similarities with the brain - offers a unique and accessible "window" to study correlates and consequences of subclinical pathology in the brain. Retinal components such as the microvasculature and retinal ganglion cell axons can now be visualized non-invasively using different retinal imaging techniques e.g., ocular fundus photography and optical coherence tomography. Advances in retinal imaging may provide new and potentially important insights into cerebrovascular neurodegenerative processes in addition to what is currently possible with neuro-imaging. In this review, we present an overview of the current literature on the application of retinal imaging in the study of dementia and stroke. We discuss clinical implications of these studies, novel state-of-the-art retinal imaging techniques and future directions aimed at evaluating whether retinal imaging can be an additional investigation tool in the study of dementia and stroke.

Optical coherence tomography: A quantitative tool to measure neurodegeneration and facilitate testing of novel treatments for tissue protection in multiple sclerosis

Optical coherence tomography (OCT) is a relatively new imaging technology that has been introduced as a powerful biomarker in neurological disease, including multiple sclerosis. In this review, OCT as an imaging technique, its reproducibility and validation in multiple sclerosis, application to other neurodegenerative diseases and future technological directions are discussed.

Severe structural and functional visual system damage leads to profound loss of vision-related quality of life in patients with neuromyelitis optica spectrum disorders

BACKGROUND

Neuromyelitis optica spectrum disorders (NMOSD) are characterized by devastating optic neuritis attacks causing more structural damage and visual impairment than in multiple sclerosis (MS). The objective of this study was to compare vision-related quality of life in NMOSD and MS patients and correlate it to structural retinal damage and visual function.

METHODS

Thirty-one NMOSD and 31 matched MS patients were included. Vision-related quality of life was assessed with the 39-item National Eye Institute Visual Function Questionnaire (NEI-VFQ). All patients underwent retinal optical coherence tomography and visual acuity and contrast sensitivity measurements.

RESULTS

Vision-related quality of life was reduced in NMOSD compared to MS patients. This difference was driven by a higher incidence of bilateral and more severe optic neuritis in the NMOSD group. Retinal thinning and visual impairment were significantly greater in the NMOSD cohort. Lower vision-related quality of life was associated with more retinal damage and reduced visual function as assessed by visual acuity and contrast sensitivity.

CONCLUSION

NMOSD-related bilateral ON-attacks cause severe structural damage and visual impairment that lead to severe loss of vision-related quality of life. The NEI-VFQ is a helpful tool to monitor vision-related quality of life in NMOSD patients.

Optical Coherence Tomography and Magnetic Resonance Imaging in Multiple Sclerosis and Neuromyelitis Optica Spectrum Disorder

Irreversible disability in multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD) is largely attributed to neuronal and axonal degeneration, which, along with inflammation, is one of the major pathological hallmarks of these diseases. Optical coherence tomography (OCT) is a non-invasive imaging tool that has been used in MS, NMOSD, and other diseases to quantify damage to the retina, including the ganglion cells and their axons. The fact that these are the only unmyelinated axons within the central nervous system (CNS) renders the afferent visual pathway an ideal model for studying axonal and neuronal degeneration in neurodegenerative diseases. Structural magnetic resonance imaging (MRI) can be used to obtain anatomical information about the CNS and to quantify evolving pathology in MS and NMOSD, both globally and in specific regions of the visual pathway including the optic nerve, optic radiations and visual cortex. Therefore, correlations between brain or optic nerve abnormalities on MRI, and retinal pathology using OCT, may shed light on how damage to one part of the CNS can affect others. In addition, these imaging techniques can help identify important differences between MS and NMOSD such as disease-specific damage to the visual pathway, trans-synaptic degeneration, or pathological changes independent of the underlying disease process. This review focuses on the current knowledge of the role of the visual pathway using OCT and MRI in patients with MS and NMOSD. Emphasis is placed on studies that employ both MRI and OCT to investigate damage to the visual system in these diseases.

Myelin-oligodendrocyte-glycoprotein (MOG) autoantibodies as potential markers of severe optic neuritis and subclinical retinal axonal degeneration

Antibodies against conformation-dependent epitopes of myelin-oligodendrocyte-glycoprotein (MOG-abs) are present in subgroups of neuromyelitis optica spectrum disorder (NMOSD), recurrent optic neuritis (rON), multiple sclerosis (MS), and anti-NMDAR encephalitis. Using optical coherence tomography (OCT) we assessed whether MOG-abs might serve as potential marker of retinal axonal degeneration. We investigated a clinically heterogeneous cohort of 13 MOG-abs-positive patients (4 MOG-abs-positive rON, 4 MOG-abs-positive adult MS, 3 MOG-abs-positive relapsing encephalomyelitis, 2 MOG-abs-positive aquaporin-4-abs-negative NMOSD). As controls, we studied 13 age, sex and ON episode(s)-matched MOG-abs and aquaporin-4-abs-negative (AQP4-abs-negative) MS patients and 13 healthy controls (HC). In addition, we investigated 19 unmatched AQP4-abs-positive MOG-abs-negative NMOSD subjects. Considering all eyes, global pRNFL [in µm, mean (SD)] was significantly reduced in MOG-abs-positive patients [72.56 (22.71)] compared to MOG-abs-negative MS [80.81 (13.55), p = 0.0128], HCs [103.54 (8.529), p = 0.0014] and NMOSD [88.32 (18.43), p = 0.0353]. Non ON eyes from MOG-abs-positive subjects showed significant subclinical atrophy of temporal pRNFL quadrants. Microcystic macular edema (MME) was observed only in eyes of MOG-abs-positive (24%) and AQP4-abs-positive NMOSD (5.6%), but not in MOG-abs-negative MS or HC (p < 0.01). MOG-abs may serve as potential marker of retinal degeneration. Specifically, MOG-abs-related OCT features predominate in temporal pRNFL quadrants (resembling the MS retinal pattern), might be more severe than AQP4-abs-positive NMOSD, indicate subclinical pathology, and may be associated with MME.

Patients with multiple sclerosis demonstrate reduced subbasal corneal nerve fibre density

BACKGROUND

Many studies in multiple sclerosis (MS) have investigated the retina. Little, however, is known about the effect of MS on the cornea, which is innervated by the trigeminal nerve. It is the site of neural-immune interaction with local dendritic cells reacting in response to environmental stimuli.

OBJECTIVE

This study aims to investigate the effect of MS on corneal nerve fibres and dendritic cells in the subbasal nerve plexus using in vivo confocal microscopy (IVCM).

METHODS

We measured the corneal nerve fibre and dendritic cell density in 26 MS patients and matched healthy controls using a Heidelberg Retina Tomograph with cornea module. Disease severity was assessed with the Multiple Sclerosis Functional Composite, Expanded Disability Status Scale, visual acuity and retinal optical coherence tomography.

RESULTS

We observed significant reduction in total corneal nerve fibre density in MS patients compared to controls. Dendritic cell density was similar in both groups. Reduced total nerve fibre density was associated with worse clinical severity but not with previous clinical trigeminal symptoms, retinal neuro-axonal damage, visual acuity or disease duration.

CONCLUSION

Corneal nerve fibre density is a promising new imaging marker for the assessment of disease severity in MS and should be investigated further.

Complement-independent retinal pathology produced by intravitreal injection of neuromyelitis optica immunoglobulin G

Background

Neuromyelitis optica (NMO), an autoimmune inflammatory disease of the central nervous system, is often associated with retinal abnormalities including thinning of the retinal nerve fiber layer and microcystic changes. Here, we demonstrate that passive transfer of an anti-aquaporin-4 autoantibody (AQP4-IgG) produces primary retinal pathology.

Methods

AQP4-IgG was delivered to adult rat retinas by intravitreal injection. Rat retinas and retinal explant cultures were assessed by immunofluorescence.

Results

Immunofluorescence showed AQP4-IgG deposition on retinal Müller cells, with greatly reduced AQP4 expression and increased glial fibrillary acidic protein by 5 days. There was mild retinal inflammation with microglial activation but little leukocyte infiltration and loss of retinal ganglion cells by 30 days with thinning of the ganglion cell complex. Interestingly, the loss of AQP4 was complement independent as seen in cobra venom factor-treated rats and in normal rats administered a mutated AQP4-IgG lacking complement effector function. Exposure of ex vivo retinal cultures to AQP4-IgG produced a marked reduction in AQP4 expression by 24 h, which was largely prevented by inhibitors of endocytosis or lysosomal acidification.

Conclusions

Passive transfer of AQP4-IgG results in primary, complement-independent retinal pathology, which might contribute to retinal abnormalities seen in NMO patients.

Clinical evaluation of microcystic macular edema in patients with glaucoma

PurposeTo investigate the prevalence of microcystic macular edema (MME) in patients with glaucoma and the relationship between glaucomatous visual field defects and MME.Patients and methodsWe analyzed 636 eyes of 341 glaucoma patients who underwent spectral domain optical coherence tomography (SD-OCT). MME was defined as vacuoles observed in the inner nuclear layer (INL) on SD-OCT. Quantitative assessment of MME area was performed using en-face imaging obtained swept-source OCT (SS-OCT) and Adobe Photoshop CS6 Extended software. These values were compared with the visual field results with the Humphrey field analyzer.ResultsMME was observed in 1.6% of eyes. The visual field mean deviation (MD), pattern standard deviation (PSD) and visual acuity was significantly worse (P= 0.023, P=0.037, and P=0.018, respectively) in eyes with MME. The average MME area was 2.38±1.43%. There was no significant correlation between visual field deficits and MME area.ConclusionsThe MME detection rate based on general inspection was 1.6%. MME in glaucomatous eyes were associated with worse MD, PSD, and visual acuity. Further research is needed to increase the number of cases to allow for more detailed analysis.

Microcystic Macular Changes in Primary Open-angle Glaucoma

PURPOSE

To describe microcystic macular changes in patients with moderate to advanced primary open-angle glaucoma.

PATIENTS AND METHODS

Eleven eyes of 6 unrelated patients were retrospectively identified based on a disproportionately preserved macular thickness on optical coherence tomography (OCT) despite severe peripapillary retinal nerve fiber layer thinning. Patient demographic, history, and examination findings were reviewed.

RESULTS

All identified patients were African American, relatively young (mean age, 43.8 y) and 5 of the 6 patients were males. Examination of individual macular OCT sections through areas of disproportionately preserved macular thickness invariably demonstrated numerous small cystic cavities within the inner nuclear layer. These microcystic changes were seen in areas of the macula that corresponded with areas of glaucoma-related ganglion cell loss, therefore mimicking the normal appearance of retinal thickness in the macular region. No other retinal pathologies were identified on the macular OCT to account for these changes.

CONCLUSIONS

This study describes microcystic macular changes in mostly young, African American males with moderate to advanced primary open-angle glaucoma. Vitreous adherence to the internal limiting membrane preventing retinal collapse is a proposed mechanism. The disproportionately preserved macular volume may confound the diagnosis of glaucoma in these patients.

Sex differences and subclinical retinal injury in pediatric-onset MS

Objective:

To assess retinal ganglion cell (RGC) injury and sex differences in axon loss in pediatric multiple sclerosis (MS).

Methods:

This is a cross-sectional evaluation of consecutive pediatric MS subjects and controls. Eyes with acute optic neuritis (ON) within 6 months of visit were excluded. Spectral domain optical coherence tomography (OCT) included peripapillary ring and macular scans with post-acquisition segmentation of retinal layers using automated software (Heidelberg v1.8.6.0). Generalized estimating equations (GEEs) measured associations of sex, history of ON, disease duration, and age with OCT outcomes.

Results:

In all, 53 MS subjects (100 eyes, median disease duration = 1.0 years, interquartile range (IQR) = 0.3, 2.5) were compared to 19 control subjects (38 eyes). Eyes with history of ON showed reduced retinal nerve fiber layer (RNFL: −26.8 µm, 95% confidence interval (CI) = −38.9, −14.8, p < 0.001) and 26% lower ganglion cell layer (GCL) volumes (−0.12 mm3, 95% CI = −0.16, −0.072, p < 0.001) compared to control eyes. Non-ON MS eyes had lower temporal RNFL (−11.9 µm, 95% CI = −18.6, −5.3, p < 0.001) and GCL volumes (−0.036 mm3, 95% CI = −0.06, −0.011, p = 0.004) than control eyes. In MS eyes, males versus females had lower global RNFL (−9.4 µm, 95% CI = −17.4, −1.33, p = 0.022) and in ON eyes had lower temporal quadrant RNFL (−9.6 µm, 95% CI = −15.1, −4.15, p = 0.001).

Conclusion:

Subclinical retinal injury occurs in pediatric-onset MS patients without a history of ON. As in adult-onset MS, substantial GCL thinning is present in eyes with prior ON. Finally, greater retinal axonal injury occurs in boys compared to girls.

Detection of retinal blood vessel changes in multiple sclerosis with optical coherence tomography

Although retinal vasculitis is common in multiple sclerosis (MS), it is not known if MS is associated with quantitative abnormalities in retinal blood vessels (BVs). Optical coherence tomography (OCT) is suitable for examining the integrity of the anterior visual pathways in MS. In this paper we have compared the size and number of retinal blood vessels in patients with MS, with and without a history of optic neuritis (ON), and control subjects from the cross-sectional retinal images from OCT. Blood vessel diameter (BVD), blood vessel number (BVN), and retinal nerve fiber layer thickness (RNFLT) were extracted from OCT images collected from around the optic nerves of 129 eyes (24 control, 24 MS + ON, 81 MS-ON) of 71 subjects. Associations between blood vessel metrics, MS diagnosis, MS disability, ON, and RNFLT were evaluated using generalized estimating equation (GEE) models. MS eyes had a lower total BVD and BVN than control eyes. The effect was more pronounced with increased MS disability, and persisted in multivariate models adjusting for RNFLT and ON history. Twenty-nine percent (29%) of MS subjects had fewer retinal blood vessels than all control subjects. MS diagnosis, disability, and ON history were not associated with average blood vessel size. The relationship between MS and lower total BVD/BVN is not accounted for by RNFLT or ON. Further study is needed to determine the relationship between OCT blood vessel metrics and qualitative retinal blood vessel abnormalities in MS.

Timing of retinal neuronal and axonal loss in MS: a longitudinal OCT study

The objective of the study was to investigate the timing of central nervous system tissue atrophy in MS by evaluating longitudinal retinal volume changes in a broadly representative cohort with disease duration across the entire arc of disease. In this longitudinal study, 135 patients with MS and 16 healthy reference subjects underwent spectral-domain optical coherence tomography (OCT) at baseline and 2 years later. Following OCT quality control, automated segmentation of the peripapillary retinal nerve fiber layer (pRNFL), macular ganglion cell-inner plexiform layer (mGCIPL) and macular inner nuclear layer (mINL) was performed. Generalized estimation equations were used to analyze longitudinal changes and associations with disease duration and clinical measures. Participants had a median disease duration at baseline of 16.4 years (range 0.1-45.4). Nearly half (44 %) of the MS patients had previously experienced MS-related optic neuritis (MSON) more than 6 months prior. The MS patients demonstrated a significant decrease over 2 years of the pRNFL (-1.1 µm, 95 % CI 1.4-0.7, p < 0.001) and mGCIPL (-1.1 µm, 95 % CI -1.4 to -0.8, p < 0.001). This thinning was most pronounced early in the course of disease. These findings were irrespective of previous episodes of MSON. No consistent pattern of change was observed for the mINL (-0.03 µm, 95 % CI -0.2 to 0.2, p = 0.795). This longitudinal study demonstrated that injury of the innermost retinal layers is found in MS and that this damage occurs most rapidly during the early stages of disease. The attenuation of atrophy with longer disease duration is suggestive of a plateau effect. These findings emphasize the importance of early intervention to prevent such injury.

Voxel Based Morphometry in Optical Coherence Tomography: Validation & Core Findings

Optical coherence tomography (OCT) of the human retina is now becoming established as an important modality for the detection and tracking of various ocular diseases. Voxel based morphometry (VBM) is a long standing neuroimaging analysis technique that allows for the exploration of the regional differences in the brain. There has been limited work done in developing registration based methods for OCT, which has hampered the advancement of VBM analyses in OCT based population studies. Following on from our recent development of an OCT registration method, we explore the potential benefits of VBM analysis in cohorts of healthy controls (HCs) and multiple sclerosis (MS) patients. Specifically, we validate the stability of VBM analysis in two pools of HCs showing no significant difference between the two populations. Additionally, we also present a retrospective study of age and sex matched HCs and relapsing remitting MS patients, demonstrating results consistent with the reported literature while providing insight into the retinal changes associated with this MS subtype.

Simultaneous Segmentation of Retinal Surfaces and Microcystic Macular Edema in SDOCT Volumes

Optical coherence tomography (OCT) is a noninvasive imaging modality that has begun to find widespread use in retinal imaging for the detection of a variety of ocular diseases. In addition to structural changes in the form of altered retinal layer thicknesses, pathological conditions may also cause the formation of edema within the retina. In multiple sclerosis, for instance, the nerve fiber and ganglion cell layers are known to thin. Additionally, the formation of pseudocysts called microcystic macular edema (MME) have also been observed in the eyes of about 5% of MS patients, and its presence has been shown to be correlated with disease severity. Previously, we proposed separate algorithms for the segmentation of retinal layers and MME, but since MME mainly occurs within specific regions of the retina, a simultaneous approach is advantageous. In this work, we propose an automated globally optimal graph-theoretic approach that simultaneously segments the retinal layers and the MME in volumetric OCT scans. SD-OCT scans from one eye of 12 MS patients with known MME and 8 healthy controls were acquired and the pseudocysts manually traced. The overall precision and recall of the pseudocyst detection was found to be 86.0% and 79.5%, respectively.