Evaluation of multiple sclerosis severity using a new OCT tool

PURPOSE

To assess the ability of a new posterior pole protocol to detect areas with significant differences in retinal nerve fiber layer (RNFL) and ganglion cell layer (GCL) thickness in patients with multiple sclerosis versus healthy control subjects; in addition, to assess the correlation between RNFL and GCL thickness, disease duration, and the Expanded Disability Status Scale (EDSS).

METHODS

We analyzed 66 eyes of healthy control subjects and 100 eyes of remitting-relapsing multiple sclerosis (RR-MS) patients. Double analysis based on first clinical symptom onset (CSO) and conversion to clinically definite MS (CDMS) was performed. The RR-MS group was divided into subgroups by CSO and CDMS year: CSO-1 (≤ 5 years) and CSO-2 (≥ 6 years), and CDMS-1 (≤ 5 years) and CDMS-2 (≥ 6 years).

RESULTS

Significant differences in RNFL and GCL thickness were found between the RR-MS group and the healthy controls and between the CSO and CDMS subgroups and in both layers. Moderate to strong correlations were found between RNFL and GCL thickness and CSO and CDMS. Furthermore, we observed a strong correlation with EDSS 1 year after the OCT examination.

CONCLUSIONS

The posterior pole protocol is a useful tool for assessing MS and can reveal differences even in early stages of the disease. RNFL thickness shows a strong correlation with disability status, while GCL thickness correlates better with disease duration.

Evaluation of peripapillary and subfoveal choroidal vascularity index in patients with multiple sclerosis

PURPOSE

To evaluate the changes in the peripapillary choroidal vascularity index (PCVI) and subfoveal choroidal vascularity index (SFCVI) in multiple sclerosis (MS) patients and healthy subjects METHODS: A total of 145 eyes of 73 patients were investigated in this cross-sectional study. 78 eyes of 39 MS patients (Group 1) and 67 eyes of 34 healthy subjects (Group 2) were evaluated. MS patients with a history of optic neuritis (ON) constituted Group 1a, those without a history of ON constituted Group 1b.

RESULTS

The mean PCVI was significantly lower in Group 1 than Group 2 (61,39±3,00 % vs 64,49±2,29 % respectively, p<0.001). The mean SFCVI scores of Group 1 was significantly lower than Group 2 (64,01±2,66 % vs. 66,87±2,14 % respectively, p<0.001). The mean PCVI of Group 1a (59,26±2,85 %) was significantly lower compared to Group 1b (62,87±2,08 %) and Group 2 (64,49±2,29 %, p1<0.001, p2<0.001). The mean SFCVI of Group 1a was significantly lower than Group 2 (64.26±2.75 % vs. 66.87±2.14 % respectively, p<0.001).

CONCLUSION

PCVI and SFCVI scores were significantly lower in MS patients compared to healthy controls. PCVI scores of MS patients who had a history of ON were significantly lower than those of patients without a previous ON attack, as were SFCVI scores. We consider that evaluation of PCVI and SFCVI might be useful for monitoring ocular involvement in patients with MS.

Progressive Functional and Neuroretinal Affectation in Patients With Multiple Sclerosis Treated With Fingolimod

BACKGROUND

To evaluate the effect of fingolimod in visual function and neuroretinal structures in patients with multiple sclerosis (MS) for a period of 1 year.

METHODS

This longitudinal and observational cohort study included 78 eyes of 78 patients with MS treated with fingolimod. All subjects were evaluated every 3 months during 12 months and compared with 32 patients treated with interferon beta. All patients were examined for high-contrast and low-contrast (2.5% and 1.25%) visual acuity (VA), contrast sensitivity vision (CSV) (using Pelli-Robson and CSV-1000E tests), color vision (Farnsworth D-15 and L'Anthony D-15 desaturated tests), and retinal structural measurements (retinal nerve fiber layer [RNFL] and ganglion cell layer [GCL] thickness) using optical coherence tomography (OCT) technology.

RESULTS

Patients with MS treated with fingolimod for a period of 1 year showed significant reduction in 100% and 1.25% contrast VA (P = 0.009 and 0.008, respectively), an alteration of contrast sensitivity and color perception (Pelli-Robson test, CSV-1000E test, Farnsworth D-15 desaturated test, and L'Anthony D-15 desaturated test; P < 0.001), GCL thickness reduction (P = 0.007), and an average macular central thickness increase of 2.6 μm (P = 0.006). Patients with MS treated with interferon beta did not show significant changes in visual function tests neither in macular thickness measurements, but they showed a significant reduction in GCL and RNFL thicknesses. The reduction in neuroretinal structures observed by OCT was significantly higher in the interferon-beta group, but patients treated with fingolimod showed a significant increase in macular central thickness and a reduction in low contrast vision (P < 0.001).

CONCLUSIONS

Patients with MS treated with fingolimod and with no clinically observable macular edema show a significant change in visual function parameters and average macular central thickness increase compared with those treated with interferon beta. These findings are probably due to subclinical macular edema produced by fingolimod, which might be considered as an indicator for pharmacovigilance of sphingosine-1-phosphate inhibitors to be improved.

Influence of Chronic Ocular Hypertension on Emmetropia: Refractive, Structural and Functional Study in Two Rat Models

Chronic ocular hypertension (OHT) influences on refraction in youth and causes glaucoma in adulthood. However, the origin of the responsible mechanism is unclear. This study analyzes the effect of mild-moderate chronic OHT on refraction and neuroretina (structure and function) in young-adult Long-Evans rats using optical coherence tomography and electroretinography over 24 weeks. Data from 260 eyes were retrospectively analyzed in two cohorts: an ocular normotension (ONT) cohort (<20 mmHg) and an OHT cohort (>20 mmHg), in which OHT was induced either by sclerosing the episcleral veins (ES group) or by injecting microspheres into the anterior chamber. A trend toward emmetropia was found in both cohorts over time, though it was more pronounced in the OHT cohort (p < 0.001), especially in the ES group (p = 0.001) and males. IOP and refraction were negatively correlated at week 24 (p = 0.010). The OHT cohort showed early thickening in outer retinal sectors (p < 0.050) and the retinal nerve fiber layer, which later thinned. Electroretinography demonstrated early supranormal amplitudes and faster latencies that later declined. Chronic OHT accelerates emmetropia in Long–Evans rat eyes towards slowly progressive myopia, with an initial increase in structure and function that reversed over time.

Past, present and future role of retinal imaging in neurodegenerative disease

Retinal imaging technology is rapidly advancing and can provide ever-increasing amounts of information about the structure, function and molecular composition of retinal tissue in humans in vivo. Most importantly, this information can be obtained rapidly, non-invasively and in many cases using Food and Drug Administration-approved devices that are commercially available. Technologies such as optical coherence tomography have dramatically changed our understanding of retinal disease and in many cases have significantly improved their clinical management. Since the retina is an extension of the brain and shares a common embryological origin with the central nervous system, there has also been intense interest in leveraging the expanding armamentarium of retinal imaging technology to understand, diagnose and monitor neurological diseases. This is particularly appealing because of the high spatial resolution, relatively low-cost and wide availability of retinal imaging modalities such as fundus photography or OCT compared to brain imaging modalities such as magnetic resonance imaging or positron emission tomography. The purpose of this article is to review and synthesize current research about retinal imaging in neurodegenerative disease by providing examples from the literature and elaborating on limitations, challenges and future directions. We begin by providing a general background of the most relevant retinal imaging modalities to ensure that the reader has a foundation on which to understand the clinical studies that are subsequently discussed. We then review the application and results of retinal imaging methodologies to several prevalent neurodegenerative diseases where extensive work has been done including sporadic late onset Alzheimer's Disease, Parkinson's Disease and Huntington's Disease. We also discuss Autosomal Dominant Alzheimer's Disease and cerebrovascular small vessel disease, where the application of retinal imaging holds promise but data is currently scarce. Although cerebrovascular disease is not generally considered a neurodegenerative process, it is both a confounder and contributor to neurodegenerative disease processes that requires more attention. Finally, we discuss ongoing efforts to overcome the limitations in the field and unmet clinical and scientific needs.

Optical coherence tomography (OCT) in neuro-ophthalmology

Optical coherence tomography (OCT) is a non-invasive medical imaging technology that is playing an increasing role in the routine assessment and management of patients with neuro-ophthalmic conditions. Its ability to characterise the optic nerve head, peripapillary retinal nerve fibre layer and cellular layers of the macula including the ganglion cell layer enables qualitative and quantitative assessment of optic nerve disease. In this review, we discuss technical features of OCT and OCT-based imaging techniques in the neuro-ophthalmic context, potential pitfalls to be aware of, and specific applications in more common neuro-ophthalmic conditions including demyelinating, inflammatory, ischaemic and compressive optic neuropathies, optic disc drusen and raised intracranial pressure. We also review emerging applications of OCT angiography within neuro-ophthalmology.

Retinal neurodegeneration in patients with end-stage renal disease assessed by spectral-domain optical coherence tomography

Spectral-domain optical coherence tomography (SD-OCT) represents a reliable tool for retinal layer volume and thickness measurement. The aim of this study was to evaluate retinal changes indicating neurodegenerative processes in patients with end-stage renal disease (ESRD) compared to healthy controls. This was a cross-sectional, single-center study comprising 32 ESRD patients and 38 controls. Sectoral retinal nerve fiber layer (RNFL) thickness and retinal layer volumes were obtained by SD-OCT. Age- and gender-adjusted retinal layer volumes such as total retinal volume (p = 0.037), ganglion cell layer volume (GCL, p = 0.003), ganglion cell layer - inner plexiform layer volume (GCL-IPL, p = 0.005) and inner retinal layer volume (IRL, p = 0.042) of the right eye were lower in ESRD patients. Inner plexiform layer volume of both eyes (IPL, right eye: p = 0.017; left eye: 0.044) was reduced, as was RNFL thickness in the temporal superior sector (right eye: p = 0.016). A subgroup analysis excluding patients with diabetes revealed that GCL (p = 0.014) and GCL-IPL volume of the right eye (p = 0.024) and temporal superior sector of the RNFL scan (p = 0.021) in ESRD patients were still significantly thinner. We observed a decrease in several retinal layer volumes and temporal RNFL thickness indicative of retinal neurodegenerative processes in patients with ESRD.

Retinal correlates of neurological disorders

Considering the retina as an extension of the brain provides a platform from which to study diseases of the nervous system. Taking advantage of the clear optical media of the eye and ever-increasing resolution of modern imaging techniques, retinal morphology can now be visualized at a cellular level in vivo. This has provided a multitude of possible biomarkers and investigative surrogates that may be used to identify, monitor and study diseases until now limited to the brain. In many neurodegenerative conditions, early diagnosis is often very challenging due to the lack of tests with high sensitivity and specificity, but, once made, opens the door to patients accessing the correct treatment that can potentially improve functional outcomes. Using retinal biomarkers in vivo as an additional diagnostic tool may help overcome the need for invasive tests and histological specimens, and offers the opportunity to longitudinally monitor individuals over time. This review aims to summarise retinal biomarkers associated with a range of neurological conditions including Alzheimer’s disease (AD), Parkinson’s disease (PD), multiple sclerosis (MS), amyotrophic lateral sclerosis (ALS) and prion diseases from a clinical perspective. By comparing their similarities and differences according to primary pathological processes, we hope to show how retinal correlates can aid clinical decisions, and accelerate the study of this rapidly developing area of research.

Functional Evaluation of the Visual Pathway in Patients with Multiple Sclerosis Using a Multifunction Stimulator Monitor

Objectives

To assess the capability of the vision monitor unit Monpack One of detecting visual function alterations in patients with multiple sclerosis (MS) and to evaluate the correlation between structural retinal parameters and functional measurements obtained with this device.

Methods

Forty-eight patients with MS and 46 healthy controls were included in a cross-sectional study. All participants underwent a complete functional evaluation of the visual pathway, which included low-contrast visual acuity (LCVA), contrast sensitivity vision (CSV), automated perimetry, multifocal visual evoked potentials (mfVEPs), and pattern electroretinogram (ERG). All tests were performed using the vision monitor unit Monpack One (Metrovision, France), a multifunction stimulator device. Retinal structural measurements were obtained in all subjects using Triton swept source optical coherence tomography (Topcon, Japan).

Results

Patients with MS presented reduced low-contrast VA (p < 0.001) and reduced CSV at medium (p=0.001, p=0.013) and low (p=0.001, p=0.002) spatial frequencies. All visual field parameters were found to be altered in MS patients compared with controls (≤0.001). Patients with MS presented lower amplitude of the P100 waveform of the mfVEP in areas corresponding to central (p < 0.001), inferonasal (p=0.001), and inferotemporal (p=0.003) retina. The pattern ERG did not show significant differences. Significant correlations were observed between structural retinal measurements and functional parameters, especially between the inner macular areas and measurements corresponding to contrast sensitivity and perimetry indexes.

Conclusions

Patients with MS present visual dysfunction detectable with the vision monitor unit Monpack One. This device may be a fast and useful tool to provide a full evaluation of axonal damage in patients with multiple sclerosis.

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

Purpose

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

Methods

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

Results

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

Conclusions

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

Retinal Tissue Perfusion in Patients with Multiple Sclerosis

Purpose: The goal of this work was to determine whether the retinal tissue perfusion (RTP) is impaired in patients with multiple sclerosis (MS). Methods: Seventy-four patients [66 relapsing-remitting MS (RRMS) and 8 clinically isolated syndrome (CIS)] and 74 age- and gender-matched healthy controls were recruited. RTP was calculated as the retinal blood flow (measured using retinal function imager) supplying the macular area divided by the corresponding tissue volume of the inner retina from the inner limiting membrane to the outer plexiform layer, as measured by ultrahigh-resolution optical coherence tomography. Results: The RTP in the MS group was 2.37 ± 0.59 nl/s/mm³ (mean ± standard deviation), which was significantly lower than the control group (4.06 ± 0.89 nl/s/mm³, P < .001), reflecting a decrease of 42%. The blood flow volume was 2.50 ± 0.50 nl/s in MS, which was 45% lower than in the control group (4.56 ± 0.91 nl/s, P < .001). In addition, the tissue volume of the inner retina was significantly lower than in the control group (P < .05). The RTP in patients with MS was significantly correlated with the retinal blood flow volume (r = 0.84, P < .001) and retinal tissue volume (r = -0.56, P < .001). However, the retinal blood flow in patients with MS was not related to the tissue volume (r = -0.06, P = .59). Conclusions: Impaired retinal tissue perfusion occurred in patients with MS, which could be developed as a possible biomarker in monitoring disease progression in MS.

Changes in peripapillary choroidal thickness in patients with multiple sclerosis

PURPOSE

To study peripapillary choroidal thickness (PPCT) around the optic disc and establish zones using a new swept source optical coherence tomography (SS-OCT) device. To evaluate PPCT differences between patients with multiple sclerosis (MS) and age- and sex-matched healthy controls.

METHODS

A total of 102 healthy subjects and 51 patients with MS were consecutively recruited. Healthy subjects were divided into teaching (n = 51, used to establish choroidal zones) and validating (n = 51, used to compare measurements with MS patients) populations. An optic disc 6.0 × 6.0-mm three-dimensional scan was obtained using SS-OCT Triton. A 26 × 26 cube-grid centred on the optic disc was generated automatically to measure PPCT. Four choroidal zones were established and used to compare PPCT between healthy controls and patients with MS.

RESULTS

Peripapillary choroidal thickness (PPCT) was significantly thinner in patients in all concentric zones (p ≤ 0.0001): 134.02 ± 16.59 μm in MS group versus 171.56 ± 12.43 μm in the control group in zone 2; 182.23 ± 20.52 versus 219.03 ± 17.99 μm, respectively, in zone 3; and 223.52 ± 10.70 versus 259.99 ± 10.29 μm, respectively, in zone 4. The choroidal thinning in the MS group tended to decrease as we distanced from the optic nerve head. Peripapillary choroidal thickness (PPCT) had a similar pattern in controls and MS; it was thicker in the superior region, followed by temporal, nasal and inferior regions.

CONCLUSION

Patients with MS showed peripapillary choroidal thinning when compared with healthy subjects in all zones around the optic disc. Peripapillary choroidal tissue shows a concentric pattern, increasing in thickness when increasing the distance from the optic nerve. The new SS-OCT could be useful for evaluating choroidal thinning in clinical practice.

Ability of Swept-Source Optical Coherence Tomography to Detect Retinal and Choroidal Changes in Patients with Multiple Sclerosis

Purpose

To evaluate the ability of new swept-source (SS) optical coherence tomography (OCT) technology to detect changes in retinal and choroidal thickness in patients with multiple sclerosis (MS).

Methods

A total of 101 healthy and 97 MS eyes underwent retinal and choroidal assessment using SS Triton OCT (Topcon). Macular thickness and peripapillary data (retinal, ganglion cell layer (GCL+, GCL++) and retinal nerve fiber layer (RNFL) thickness) were analyzed, including choroidal thickness evaluation.

Results

Significant macular thinning was observed in all ETDRS areas (p < 0.001) in MS patients. Peripapillary retinal, RNFL, and GCL ++ thickness showed a significant reduction in patients in all sectors (p < 0.001) except in the nasal quadrant/sector (p > 0.05). GCL+ measurements were found to be reduced in the nasal (p=0.003), inferonasal (p=0.045), and temporal (p=0.001) sectors and total thickness (p < 0.001). Choroidal thickness was reduced in the outer macular ring in MS patients compared with controls (p=0.038).

Conclusion

New swept-source technology for OCT devices detects retinal thinning in MS patients, providing increased depth analysis of the choroid in these patients. MS patients present reduced retinal and choroidal thickness in the macular area and reduced peripapillary retinal, RNFL, and GCL thickness.

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.

Optical Coherence Tomography as a Biomarker for Diagnosis, Progression, and Prognosis of Neurodegenerative Diseases

Neurodegenerative diseases present a current challenge for accurate diagnosis and for providing precise prognostic information. Developing imaging biomarkers for multiple sclerosis (MS), Parkinson disease (PD), and Alzheimer's disease (AD) will improve the clinical management of these patients and may be useful for monitoring treatment effectiveness. Recent research using optical coherence tomography (OCT) has demonstrated that parameters provided by this technology may be used as potential biomarkers for MS, PD, and AD. Retinal thinning has been observed in these patients and new segmentation software for the analysis of the different retinal layers may provide accurate information on disease progression and prognosis. In this review we analyze the application of retinal evaluation using OCT technology to provide better understanding of the possible role of the retinal layers thickness as biomarker for the detection of these neurodegenerative pathologies. Current OCT analysis of the retinal nerve fiber layer and, specially, the ganglion cell layer thickness may be considered as a good biomarker for disease diagnosis, severity, and progression.

Retina measurements for diagnosis of Parkinson disease

PURPOSE

To test the diagnostic ability of spectral domain optical coherence tomography for the detection of Parkinson disease using retinal nerve fiber layer and retinal thickness parameters. Retinal pigment epithelium produces levodopa.

METHODS

Patients with Parkinson disease (n = 111) and healthy subjects (n = 200) were enrolled. The Spectralis optical coherence tomography was used to obtain retinal nerve fiber layer thickness and retinal measurements. Two linear discriminant functions (LDFs) were developed, one using retinal nerve fiber layer parameters and another using retinal thickness. A validating set was used to test the performance of both LDFs. Receiver operating characteristic curves were plotted and compared with the standard parameters provided by optical coherence tomography for both LDFs. Sensitivity and specificity were used to evaluate diagnostic performance.

RESULTS

The Retinal LDF combines only retinal thickness parameters and provided the best performance: 31.173 + 0.026 × temporal outer - 0.267 × superior outer + 0.159 × nasal outer - 0.197 × inferior outer - 0.060 × superior inner + 0.049 × foveal thickness. The largest areas under the receiver operating characteristic curve were 0.902 for Retinal LDF. The Retinal LDF yielded the highest sensitivity values.

CONCLUSION

Measurements of retinal thickness differentiate between subjects who are healthy and those with advanced Parkinson disease.

Detecting Optic Atrophy in Multiple Sclerosis Patients Using New Colorimetric Analysis Software: From Idea to Application

Neuro-ophthalmologists typically observe a temporal pallor of the optic disc in patients with multiple sclerosis. Here, we describe the emergence of an idea to quantify these optic disc color changes in multiple sclerosis patients. We recruited 12 multiple sclerosis patients with previous optic neuritis attack and obtained photographs of their optic discs. The Laguna ONhE, a new colorimetric software using hemoglobin as the reference pigment in the papilla, was used for the analysis. The papilla of these multiple sclerosis patients showed greater pallor, especially in the temporal sector. The software detected the pallor and assigned hemoglobin percentages below normal reference values. Measurements of optic disc hemoglobin levels obtained with the Laguna ONhE software program had good ability to detect optic atrophy and, consequently, axonal loss in multiple sclerosis patients. This new technology is easy to implement in routine clinical practice.

OCT: New perspectives in neuro-ophthalmology

Optical coherence tomography (OCT) has become essential to evaluate axonal/neuronal integrity, to assess disease progression in the afferent visual pathway and to predict visual recovery after surgery in compressive optic neuropathies. Besides that OCT testing is considered a powerful biomarker of neurodegeneration and a promising outcome measure for neuroprotective trials in multiple sclerosis (MS). Currently, spectral-domain OCT (SD-OCT) technology allows quantification of retinal individual layers. The Ganglion Cell layer (GCL) investigation has become one of the most useful tools from a neuro-ophthalmic perspective. It has a high correlation with perimetry, is predictive of future progression and is a highly sensitive, specific of several neuro-ophthalmic pathologies. Moreover the superior correlation with clinical measures compared to peripapillary retinal nerve fiber layer (pRNFL) suggests that GCL analysis might be a better approach to examine MS neurodegeneration. In disorders with optic disk edema, such as ischemic optic neuropathy, papillitis and papilledema, reduction in RNFL thickness caused by axonal atrophy is difficult to distinguish from a swelling resolution. In this setting, and in buried optic nerve head drusen (ONHD), GCL analysis may provide more accurate information than RNFL analysis and it might be an early structural indicator of irreversible neuronal loss. Enhanced depth imaging OCT (EDI-OCT) provides in vivo detail of ONHD, allowing to evaluate and quantify the drusen dimensions. OCT is improving our knowledge in hereditary optic neuropathies. Furthermore, there is growing evidence about the role of OCT as an adjunctive biomarker of disorders such as Alzheimer and Parkinson's disease.

Comparative diagnostic accuracy of ganglion cell-inner plexiform and retinal nerve fiber layer thickness measures by Cirrus and Spectralis optical coherence tomography in relapsing-remitting multiple sclerosis

Objective. To estimate sensitivity and specificity of several optical coherence tomography (OCT) measurements for detecting retinal thickness changes in patients with relapsing-remitting multiple sclerosis (RRMS), such as macular ganglion cell-inner plexiform layer (GCIPL) thickness measured with Cirrus (OCT) and peripapillary retinal nerve fiber layer (pRNFL) thickness measured with Cirrus and Spectralis OCT. Methods. Seventy patients (140 eyes) with RRMS and seventy matched healthy subjects underwent pRNFL and GCIPL thickness analysis using Cirrus OCT and pRNFL using Spectralis OCT. A prospective, cross-sectional evaluation of sensitivities and specificities was performed using latent class analysis due to the absence of a gold standard. Results. GCIPL measures had higher sensitivity and specificity than temporal pRNFL measures obtained with both OCT devices. Average GCIPL thickness was significantly more sensitive than temporal pRNFL by Cirrus (96.34% versus 58.41%) and minimum GCIPL thickness was significantly more sensitive than temporal pRNFL by Spectralis (96.41% versus 69.69%). Generalised estimating equation analysis revealed that age (P = 0.030), optic neuritis antecedent (P = 0.001), and disease duration (P = 0.002) were significantly associated with abnormal results in average GCIPL thickness. Conclusion. Average and minimum GCIPL measurements had significantly better sensitivity to detect retinal thickness changes in RRMS than temporal pRNFL thickness measured by Cirrus and Spectralis OCT, respectively.

Relationship between Structural and Functional Assessment of the Visual System in Mildly Disabled Relapsing-Remitting Multiple Sclerosis Patients

Studies that explored the anterior visual pathway in the patients with multiple sclerosis (MS) have demonstrated contradictory results about the correlation between structural and functional status of optic nerve and retina. We aimed to investigate the functional and structural findings in our cohort of mildly disabled relapsing-remitting MS patients. A total of 134 eyes (80 eyes of the patients with MS and 54 eyes of the control group) were investigated. Eyes of MS patients were divided into two groups-as eyes with history of optic neuritis (ON group) and without history of optic neuritis (NON group). Ophthalmological investigation including visual evoked potentials, standard automated perimetry, and optical coherence tomography were performed for all participants. Retinal and macular thicknesses were significantly decreased in ON and NON groups compared with controls. Also, visual evoked potential latencies and visual field loss were worse in the both MS groups compared with control group. We did not find any correlation between visual evoked potentials and retinal or macular thickness values but visual field parameters were correlated between retinal and macular layer loss in the NON group. According to our results and some previous studies, although both functional and structural changes were detected in patients with MS, functional status markers do not always show parallelism (or synchrony) with structural changes, especially in eyes with history of optic neuritis.

Neural networks to identify multiple sclerosis with optical coherence tomography

PURPOSE

To compare axonal loss in ganglion cells detected with spectral-domain optical coherence tomography (OCT) in eyes of patients with multiple sclerosis (MS) versus healthy control subjects using an artificial neural network (ANN). To analyse the capability of the ANN technique to improve the detection of retinal nerve fibre layer (RNFL) damage in patients with multiple sclerosis.

METHODS

Patients with multiple sclerosis (n = 106) and age-matched healthy subjects (n = 115) were enrolled. The Spectralis OCT system was used to obtain the circumpapillary RNFL thickness in both eyes. The 768 RNFL thickness measurements provided by the Spectralis OCT were performed to obtain thickness measurements from 24 uniformly divided locations around the peripapillary RNFL. The performance of the ANN technique for identifying RNFL loss in patients with multiple sclerosis was evaluated. Receiver-operating characteristic (ROC) curves were used to display the ability of the test to discriminate between MS and healthy eyes in our population. ROC curves obtained using ANN and parameters provided by OCT (mean and 6 sector thicknesses) were compared.

RESULTS

The capability of the ANN technique to detect RNFL loss in patients with multiple sclerosis compared with healthy subjects was good. The area under the ROC curve was 0.945. Compared with the OCT-provided parameters, the ANN had the largest area under the ROC curve.

CONCLUSIONS

Measurements of RNFL thickness obtained with Spectralis OCT have a good ability to differentiate between healthy and individuals with multiple sclerosis. Based on the area under the ROC curve, the ANN performed better than any single OCT parameter.

Three-dimensional geometries representing the retinal nerve fiber layer in multiple sclerosis, optic neuritis, and healthy eyes

BACKGROUND

To represent and interpret the three-dimensional (3D) geometry and the distribution of the axonal damage to the retinal nerve fiber layer (RNFL) in patients with multiple sclerosis (MS) compared with healthy subjects. To analyze alterations in RNFL morphology in eyes of MS patients with or without previous episodes of optic neuritis (ON).

METHODS

MS patients (n = 122) and age-matched healthy subjects (n = 108) were enrolled. The Spectralis optical coherence tomography system was used to determine the circumpapillary RNFL thickness. The 768 RNFL thickness measurements were used to evaluate thickness measurements in patients with or without antecedent ON and to design a 3D reconstruction of the RNFL thickness representing the mechanobiologic tissue response to neurodegeneration caused by MS and ON episodes.

RESULTS

RNFL thickness was decreased in MS patients, and was higher in the MS group with previous ON. Statistical analysis and 3D RNFL reconstruction revealed greater damage to the ganglionar cells in the superonasal RNFL area (101.77 µm in MS vs. 125.47 µm in healthy subjects) and in the inferotemporal RNFL (119.05 µm in MS eyes and 149.26 µm in healthy eyes).

CONCLUSIONS

The 3D representation of RNFL thickness based on measurements allows physicians to better observe damage in the temporal areas, especially in patients with previous ON.

Color-code agreement among stratus, cirrus, and spectralis optical coherence tomography in relapsing-remitting multiple sclerosis with and without prior optic neuritis

PURPOSE

To evaluate the agreement of retinal nerve fiber layer (RNFL) color codes among Stratus, Cirrus, and Spectralis optical coherence tomography (OCT) in patients with relapsing-remitting multiple sclerosis.

DESIGN

Prospective cohort study.

METHODS

In 140 eyes from 70 patients having relapsing-remitting multiple sclerosis from January 2011 to September 2011, peripapillary RNFL thickness was measured using the fast RNFL program by Stratus, the optic disc cube protocol by Cirrus, and the N-site axonal analysis by Spectralis.

RESULTS

Overall, a moderate to good RNFL color code agreement was found (0.435-0.884), except for the nasal quadrant. The temporal quadrant was the most abnormal color coding by both Cirrus (64.7%) and Spectralis (61.7%) in both the optic neuritis (ON) and non-ON group and by Stratus (58.8%) in the ON group. Abnormal temporal RNFL color-code rate was significantly higher in ON eyes than non-ON eyes by Cirrus (P < .001), Stratus (P < .001), and Spectralis (P = .030). Overall, Cirrus significantly displayed abnormal findings while both Stratus and Spectralis displayed normal results for the inferior quadrant (P < .05). On the other hand, Spectralis OCT showed a significantly higher rate of abnormal findings while Cirrus displayed normal results for the temporal quadrant in non-ON eyes (P < .001).

CONCLUSIONS

We found a substantial color-code disagreement among devices in patients with relapsing-remitting multiple sclerosis regarding the ON antecedent. In non-ON eyes, Spectralis yielded a significantly higher thinning for temporal quadrant than Cirrus, suggesting that N-site axonal analysis could define axonal damage in relapsing-remitting multiple sclerosis patients earlier than conventional RNFL analysis.

Effectiveness of averaging strategies to reduce variance in retinal nerve fibre layer thickness measurements using spectral-domain optical coherence tomography

BACKGROUND

Automated detection of subtle changes in peripapillary retinal nerve fibre layer thickness (RNFLT) over time using optical coherence tomography (OCT) is limited by inherent image quality before layer segmentation, stabilization of the scan on the peripapillary retina and its precise placement on repeated scans. The present study evaluates image quality and reproducibility of spectral domain (SD)-OCT comparing different rates of automatic real-time tracking (ART).

METHODS

Peripapillary RNFLT was measured in 40 healthy eyes on six different days using SD-OCT with an eye-tracking system. Image brightness of OCT with unaveraged single frame B-scans was compared to images using ART of 16 B-scans and 100 averaged frames. Short-term and day-to-day reproducibility was evaluated by calculation of intraindividual coefficients of variation (CV) and intraclass correlation coefficients (ICC) for single measurements as well as for seven repeated measurements per study day.

RESULTS

Image brightness, short-term reproducibility, and day-to-day reproducibility were significantly improved using ART of 100 frames compared to one and 16 frames. Short-term CV was reduced from 0.94 ± 0.31 % and 0.91 ± 0.54 % in scans of one and 16 frames to 0.56 ± 0.42 % in scans of 100 averaged frames (P ≤ 0.003 each). Day-to-day CV was reduced from 0.98 ± 0.86 % and 0.78 ± 0.56 % to 0.53 ± 0.43 % (P ≤ 0.022 each). The range of ICC was 0.94 to 0.99. Sample size calculations for detecting changes of RNFLT over time in the range of 2 to 5 μm were performed based on intraindividual variability.

CONCLUSION

Image quality and reproducibility of mean peripapillary RNFLT measurements using SD-OCT is improved by averaging OCT images with eye-tracking compared to unaveraged single frame images. Further improvement is achieved by increasing the amount of frames per measurement, and by averaging values of repeated measurements per session. These strategies may allow a more accurate evaluation of RNFLT reduction in clinical trials observing optic nerve degeneration.

Longitudinal follow-up of vision in a neuromyelitis optica cohort

BACKGROUND

Neuromyelitis optica (NMO) is an inflammatory disease associated with optic neuritis and myelitis. Recently, several studies showed that optical coherence tomography (OCT) could be an interesting method for the evaluation of disease severity; however, to date there are no studies with a longitudinal follow-up of visual function in NMO. The aim of this study was to assess the ability of OCT to evaluate the progression of visual dysfunction in NMO.

PATIENTS AND METHODS

A group of 30 NMO patients (thus, 60 eyes), comprised of 20 women and 10 men with a mean age of 43.7 +/- 12.3 years, were prospectively evaluated clinically and by a whole neuro-ophthalmological work-up, including: visual acuity (VA), fundoscopy, visual evoked potential (VEP), visual field (VF) and optical coherence tomography (OCT). All patients were tested at baseline (after a mean disease duration of 6.1 years) and after a mean time of follow-up of 18 months (range: 12-36 months).

RESULTS

Mean VA was similar at the two evaluation times (0.77 +/- 0.36 versus 0.77 +/- 0.35). The mean VF defect decreased slightly, but the difference was not significant (-5.9 +/- 1.3 dB versus -5.3 +/- 1.3 dB). In contrast, the mean retinal thickness seen on OCT decreased from 87.4 +/- 23.3 µm to 79.7 +/- 22.4 µm (p = 0.006). These modifications were only observed in eyes with a past or a recent history of optic neuritis (-15.1 µm; p < 0.001) and not in eyes without any history of optic neuritis (-2.4 µm; not significant). Also, they occurred independently of the occurrence of relapses (n = 13) and especially optic neuritis episodes; however, the number of optic neuritis episodes was low (n = 5).

CONCLUSION

OCT seems to be a more sensitive test than VA or VF for monitoring ophthalmological function in NMO and it seems to be helpful for the detection of infra-clinical episodes in patients with a past history of optic neuritis. Our results suggest that this easily performed technique should be used in the follow-up of NMO, but complementary studies are warranted to confirm its interest at an individual level.

[Optical coherence tomography in neuro-ophthalmology]

INTRODUCTION

Optical coherence tomography (OCT) is a potential tool for diagnosis and follow-up in diseases of the anterior visual pathway in that it provides a reproducible and reliable quantification of retinal nerve fiber layer (RNFL) thickness. A review of the literature was conducted to define the utility of OCT in neuro-ophthalmology.

MATERIALS AND METHODS

The clinical applications of RNFL thickness measurement by OCT time domain were analyzed. The PubMed search engine enabled us to select the relevant publications, using the following keywords: "optic neuropathy", "retinal nerve fiber layer thickness", and "optical coherence tomography". Publications concerning glaucoma were excluded from this review.

RESULTS

The course of RNFL thickness depends on the underlying disease: (I) progressive reduction toward atrophy (e.g., optic neuritis, chiasmal compression) or (II) initial increase in RNFL thickness followed by a reduction toward (IIa) normalization (papilledema) or (IIb) atrophy (anterior ischemic optic neuropathy, Leber hereditary optic neuropathy).

DISCUSSION

Depending on the type of anterior visual pathway impairment, OCT provides RNFL data relevant for diagnosis, follow-up, and prognosis. As in macular disease, OCT has become an important clinical tool for routine disease assessment in neuro-ophthalmology.

Characterization of structure and function of the mouse retina using pattern electroretinography, pupil light reflex, and optical coherence tomography

OBJECTIVE

To perform in vivo analysis of retinal functional and structural parameters in healthy mouse eyes.

ANIMAL STUDIED

Adult C57BL/6 male mice (n = 37).

PROCEDURES

Retinal function was evaluated using pattern electroretinography (pERG) and the chromatic pupil light reflex (cPLR). Structural properties of the retina and nerve fiber layer (NFL) were evaluated using spectral-domain optical coherence tomography (SD-OCT).

RESULTS

The average pERG amplitudes were found to be 11.2 ± 0.7 μV (P50-N95, mean ± SEM), with an implicit time for P50-N95 interval of 90.4 ± 5.4 ms. Total retinal thickness was 229.5 ± 1.7 μm (mean ± SEM) in the area centralis region. The thickness of the retinal nerve fiber layer (mean ± SEM) using a circular peripapillary retinal scan centered on the optic nerve was 46.7 ± 0.9 μm (temporal), 46.1 ± 0.9 μm (superior), 45.8 ± 0.9 μm (nasal), and 48.4 ± 1 μm (inferior). The baseline pupil diameter was 2.1 ± 0.05 mm in darkness, and 1.1 ± 0.05 and 0.56 ± 0.03 mm after stimulation with red (630 nm, luminance 200 kcd/m(2)) or blue (480 nm, luminance 200 kcd/m(2)) light illumination, respectively.

CONCLUSIONS

Pattern electroretinography, cPLR and SD-OCT analysis are reproducible techniques, which can provide important information about retinal and optic nerve function and structure in mice.

Nerve fiber layer and macular thinning measured with different imaging methods during the course of acute optic neuritis

PURPOSE

To compare retinal nerve fiber layer thickness (RNFLT) and inner macula thickness changes measured with Fourier-domain optical coherence tomography (FD-OCT) and scanning laser polarimetry during the course of acute optic neuritis (ON).

METHODS

Nine eyes of 7 consecutive patients with multiple sclerosis (MS) were prospectively imaged from the onset of ON for 6 to 12 months. Nine healthy eyes were imaged for 12 to 19 months.

RESULTS

Retinal nerve fiber layer thickness measured with FD-OCT initially increased in all eyes with diffuse optic disc edema. Inner macula thickness and polarimetric RNFLT decreased already in the acute phase, in all eyes. All parameters stabilized at 2 to 5 months. The relative structural loss was different with the different methods. Poor image quality with polarimetry occurred in 2 eyes in the acute phase of ON. In the control eyes all parameters were stable.

CONCLUSIONS

Change of RNFLT and macular thickness during the course of acute ON in MS strongly depends on the method used for the measurement. Inner macula thickness, measured with FD-OCT, was especially useful for the follow-up, since it was not influenced by initial disc edema and had consistently high image quality.

Sight-dependent quality of life and ophthalmic findings in a group of Brazilian patients with multiple sclerosis

OBJECTIVE

To assess the visual quality of life in patients with multiple sclerosis (MS), and to observe whether this parameter could be correlated to the findings of the ophthalmologic examination.

METHOD

The translated and validated 25-Item National Eye Institute Visual Function Questionnaire (VFQ-25) was used to assess the visual quality of life. Clinical data on MS, visual acuity, visual fields, optic coherence tomography (OCT) and disc cupping were used for assessing correlation with VFQ-25.

RESULTS

The mean VFQ-25 value was 78.6 ± 18.2% in 27 patients. VFQ-25 did not correlate with patients' ages, with disability (EDSS), disease duration or medication use. Visual acuity showed a relatively poor (<60%) correlation to VFQ-25, while no correlation could be established between visual fields, OCT and disc cupping with VFQ-25.

CONCLUSION

MS patients present several alterations in their eyes and sight that cannot be assessed by isolated measures. Ophthalmological examination of these patients must include many parameters not usually used in standard ophthalmologic consultations.

Color vision is strongly associated with retinal thinning in multiple sclerosis

OBJECTIVES

Multiple Sclerosis (MS) frequently causes injury to the anterior visual pathway (AVP), impairing quality of life due to visual dysfunction. Development of biomarkers in MS is a high priority and both low-contrast visual acuity (LCVA) and time-domain optical coherence tomography (TD-OCT) have been proposed as candidates for this purpose. We sought to assess whether psychophysical assessments of color vision are similarly correlated with structural measures of AVP injury, and therefore augment measures of visual disability in MS.

METHODS

We studied the association between high-contrast visual acuity (HCVA), LCVA, color vision (Hardy-Rand-Rittler plates (HRR) and Lanthony D15 tests) and OCT, using both high-resolution spectral-domain OCT (SD-OCT; Spectralis, Heidelberg Engineering, Germany) and TD-OCT (Stratus, Carl Zeiss, US) in a cohort of 213 MS patients (52 with previous optic neuritis) and 47 matched controls in a cross-sectional study.

RESULTS

We found that MS patients have impairments in HCVA and LCVA (p < 0.001) but that they suffer from even more profound abnormalities in color discrimination (p < 0.0001). We found strong correlation between color vision and SD-OCT measures of retinal nerve fiber layer (RNFL) thickness (average RNFL, r = 0.594, p < 0.001) and papillomacular bundle thickness (r = -0.565, p < 0.001). The correlation between OCT scores and functional visual impairments of all types was much stronger for SD-OCT than for TD-OCT.

CONCLUSION

Our results indicate that color vision is highly correlated with these OCT scores when compared with traditional measures of visual acuity. Also we found that SD-OCT is superior to TD-OCT for detecting anterior visual pathway damage in MS. This makes both color-visual measures and SD-OCT strong candidate biomarkers of disease progression.

Optical coherence tomography in multiple sclerosis and neuromyelitis optica: an update

Optical coherence tomography (OCT) uses light interference patterns to produce a cross-sectional image of the retina. It is capable of measuring the unmyelinated axons of the retinal ganglionar cells as they converge on the optic disc. In a disease like multiple sclerosis (MS), in which axonal loss has been identified as an important cause of sustained disability, it may prove an invaluable tool. OCT has demonstrated that axonal loss occurs after each episode of optic neuritis and that the degree of axonal loss is correlated to visual outcomes. Furthermore, axonal loss occurs in MS even in the absence of inflammatory episodes, and the degree of this loss is correlated with the duration of the disease process, with more thinning as the disease advances and in progressive forms. Thus, OCT retinal nerve fiber layer measurements may represent an objective outcome measure with which to evaluate the effect of treatment.

Effect of optic neuritis on progressive axonal damage in multiple sclerosis patients

Objective: The objective of this research was to study the effect of optic neuritis (ON) on axonal damage in multiple sclerosis (MS) patients. Specifically, we compared changes over 2 years in the retinal nerve fibre layer (RNFL) between affected and contralateral eyes in MS patients with a prior history of ON.

Methods: Thirty-four patients with one unilateral definitive episode of ON were included and underwent a complete ophthalmic examination, optical coherence tomography (OCT), scanning laser polarimetry, visual evoked potentials (VEP) and pattern electroretinogram (pERG). All patients were re-evaluated at 12 and 24 months. Parameters were compared between ON-affected and contralateral eyes in an initial exploration and over the course of the follow-up. Correlations between parameter changes were analysed.

Results: RNFL thickness and functional parameters showed more affection in ON eyes ( p ≤ 0.05), but changes in measurements during the study were similar between both groups of eyes.

Conclusions: Progressive axonal loss can be detected in the optic nerve, but ON is not a risk factor for increased chronic damage in MS patients without ophthalmic relapses. Loss of the RNFL is caused by progressive degeneration associated with the disease.

Optical coherence tomography in multiple sclerosis: a systematic review and meta-analysis

Optical coherence tomography (OCT) is a new method that could aid analysis of neurodegeneration in multiple sclerosis (MS) by capturing thinning of the retinal nerve fibre layer (RNFL). Meta-analyses of data for time domain OCT show RNFL thinning of 20.38 microm (95% CI 17.91-22.86, n=2063, p<0.0001) after optic neuritis in MS, and of 7.08 microm (5.52-8.65, n=3154, p<0.0001) in MS without optic neuritis. The estimated RNFL thinning in patients with MS is greater than the extent expected in normal ageing, probably because of retrograde trans-synaptic degeneration and progressive loss of retinal ganglion cells, in addition to the more pronounced thinning caused by optic neuritis if present. RNFL thickness correlates with visual and neurological functioning as well as with paraclinical data. Developments that could improve understanding of the relation between structure and function in MS pathophysiology include spectral or Fourier domain OCT technology, polarisation-sensitive OCT, fluorescence labelling, structural assessment of action-potential propagation, and segmentation algorithms allowing quantitative assessment of retinal layers.

Retinal nerve fiber layer thickness in subgroups of multiple sclerosis, measured by optical coherence tomography and scanning laser polarimetry

Optical coherence tomography (OCT) and scanning laser polarimetry (GDx ECC) are non-invasive methods used to assess retinal nerve fiber layer (RNFL) thickness, which may be a reliable tool used to monitor axonal loss in multiple sclerosis (MS). The objectives of this study are (1) to compare OCT with the GDx ECC; (2) to assess and compare the RNFL thickness in subgroups of MS. Ophthalmologic examination and RNFL assessment by OCT and GDx were performed in 65 MS patients (26 relapsing-remitting (RRMS), ten secondary-progressive (SPMS), 29 primary-progressive (PPMS)). Twenty-eight patients (43%) had a history of optic neuritis (ON). Adjustments were made for age and disease duration. RNFL thickness was reduced in eyes with previous ON (p < 0.01). No differences were found between PPMS and relapse-onset MS. OCT and GDx ECC measurements were moderately correlated (rho = 0.73, p < 0.01). Visual field-mean deviation (MD) values correlated with OCT means (r = 0.44, p < 0.01) and GDx ECC TSNIT average (r = 0.41, p < 0.01). In patients without previous ON, EDSS correlated with MD (r = −0.36, p < 0.01), visual field-pattern standard deviation (PSD) (r = 0.30, p < 0.05), OCT means (r = −0.31–0.30, p < 0.05) and macular volume (r = −0.37, p < 0.01). For MSIS-29 physical impact score, significant correlations were found with MD (r = −0.48, p < 0.01) and PSD (r = 0.48, p < 0.01). Conclusions: No differences between PPMS and relapse-onset MS subgroups were found. RNFL thickness was reduced in eyes with previous ON. Although OCT and GDx ECC findings were moderately correlated and showed significant correlations with measures of visual function in patients without previous ON, EDSS correlated significantly with visual and OCT measures, but not with GDx ECC.