The relationship between visual field and retinal nerve fiber layer measurements in patients with multiple sclerosis

The complex relation between visual complaints and decline in visual, visuoperceptual and cognitive functions in people with multiple sclerosis

People with multiple sclerosis (pwMS) report many different visual complaints, but not all of them are well understood. Decline in visual, visuoperceptual and cognitive functions do occur in pwMS, but it is unclear to what extend those help us understand visual complaints. The purpose of this cross-sectional study was to explore the relation between visual complaints and decline in visual, visuoperceptual and cognitive functions, to optimize care for pwMS. Visual, visuoperceptual and cognitive functions of 68 pwMS with visual complaints and 37 pwMS with no or minimal visual complaints were assessed. The frequency of functional decline was compared between the two groups and correlations were calculated between visual complaints and the assessed functions. Decline in several functions occurred more frequently in pwMS with visual complaints. Visual complaints may be an indication of declined visual or cognitive functioning. However, as most correlations were not significant or weak, we cannot infer that visual complaints are directly related to functions. The relationship may be indirect and more complex. Future research could focus on the overarching cognitive capacity that may contribute to visual complaints. Further research into these and other explanations for visual complaints could help us to provide appropriate care for pwMS.

SUBCLINICAL OPTIC NEURITIS

Acute optic neuritis is often associated with multiple sclerosis. It is considered to be the most common ocular symptom of multiple sclerosis. In addition to acute optic neuritis, in patients with multiple sclerosis, subclinical optic neuritis is also described. It is characterized by slow progression and bilateral involvement, thus being unnoticed by the patient. The purpose of the present study was to assess vision impairment in multiple sclerosis patients without a history of acute optic neuritis, using a number of functional tests including visual field testing by Octopus 101 perimetry N1 program, contrast sensitivity testing by Pelli Robson chart, and color vision by Ishihara pseudoisochromatic plates. The study included 35 multiple sclerosis patients aged 18-50 years, without subjective signs of vision impairment and visual acuity 1.0 according to Snellen. Visual field defects were found in 28 patients. The most common defects of visual fields were retinal sensitivity depression in peripheral zone and nerve fiber bundle defect. Reduced contrast sensitivity was found in 30 (86%) patients. Study results indicated multiple sclerosis patients free from signs of optic neuritis to suffer vision function impairment, as demonstrated by Octopus perimetry and contrast sensitivity testing with Pelli Robson charts.

Multiple Sclerosis: What Methods are Available for the Assessment of Subclinical Visual System Damage?

We aimed to assess the visual fields and optical coherence tomography (OCT) measurements in patients with multiple sclerosis (MS) to detect subclinical visual system disease. The study included 15 MS patients with previous optic neuritis (Group I), 17 MS patients without previous optic neuritis (Group II), and 14 healthy controls (Group III). Each subject underwent standard automated perimetry (SAP), frequency doubling technology perimetry (FDTP), and OCT. The mean deviation of SAP in Group I was lower than those in Groups II (p = .018) and III (p = .001). The pattern standard deviation of SAP in Group I was higher than those in Group III (p < .0001). The mean deviation of FDTP in Groups I and II was lower than those in Group III (p = .0001 and p = .016, respectively). The temporal quadrant of the retinal nerve fibre layer in Group I was thinner than those in Groups II and III (p = .005 and p = .003, respectively). The mean macular volume in Group I was thinner than those in Groups II and III (p = .004 and p = .002, respectively). A single method is inadequate for establishing early and/or mild visual impairment in MS. All conventional and non-conventional techniques are complementary in demonstrating subclinical visual damage in MS.

Retinal nerve fiber layer characteristics in patients with spontaneous intracranial hypotension: a retrospective case series

OBJECTIVE

To evaluate changes in retinal nerve fiber layer (RNFL) and macular thicknesses, included ganglion cell-inner plexiform layer (GCIPL) thickness, in patients with spontaneous intracranial hypotension (SIH).

METHODS

This was a retrospective, nonrandom, observational case series study. Comprehensive ophthalmic examinations and systemic examinations were performed. Spectral domain optical coherence tomography angiography scanning was used to measure peripapillary RNFL thickness and macular volume.

RESULTS

In total, 108 eyes in 54 patients with SIH were evaluated; these were compared with 108 eyes in 54 healthy controls. The mean ages were 38.2 ± 9.4 years (patients with SIH) and 38.9 ± 9.4 years (healthy controls). In both groups, 33 patients were women (61.1%). The peripapillary RNFL and GCIPL were thinner in patients with SIH than in healthy controls (100.08 ± 9.94 µm vs 104.83 ± 8.35 µm and 81.46 ± 5.67 µm vs 85.67 ± 4.57 µm, respectively). Among patients with SIH, the GCIPL was thinner in patients with visual field defects (79.81 ± 5.62 µm vs 82.39 ± 5.12 µm).

CONCLUSIONS

The RNFL and GCIPL were thinner in patients with SIH than in healthy controls. The GCIPL was thinner in eyes with visual field defects among patients with SIH.

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

BACKGROUND

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Intrinsically photosensitive retinal ganglion cell-driven pupil responses in patients with traumatic brain injury

Previous findings regarding intrinsically photosensitive retinal ganglion cell (ipRGC) function after traumatic brain injury (TBI) are conflicting. We examined ipRGC-driven pupil responses in civilian TBI and control participants using two pupillography protocols that assessed transient and adaptive properties: (1) a one second (s) long wavelength "red" stimulus (651 nm, 133 cd/m²) and 10 increasing intensities of 1 s short wavelength "blue" stimuli (456 nm, 0.167 to 167 cd/m²) with a 60 s interstimulus interval, and (2) two minutes of 0.1 Hz red stimuli (33 cd/m²), followed by two minutes of 0.1 Hz blue stimuli (16 cd/m²). For Protocol 1, constriction amplitude and the 6 s post illumination pupil response (PIPR) were calculated. For Protocol 2, amplitudes and peak velocities of pupil constriction and redilation were calculated. For Protocol 1, constriction amplitude and the 6 s PIPR were not significantly different between TBI patients and control subjects for red or blue stimuli. For Protocol 2, pupil constriction amplitude attenuated over time for red stimuli and potentiated over time for blue stimuli across all subjects. Constriction and redilation velocities were similar between groups. Pupil constriction amplitude was significantly less in TBI patients compared to control subjects for red and blue stimuli, which can be attributed to age-related differences in baseline pupil size. While TBI, in addition to age, may have contributed to decreased baseline pupil diameter and constriction amplitude, responses to blue stimulation suggest no selective damage to ipRGCs.

Binocular Vision in Patients with Multiple Sclerosis

PURPOSE

Oculomotor disorders have been reported in multiple sclerosis (MS) in up to 80% of cases. There have been studies evaluating binocular vision in several neurological diseases, but not in MS. Considering that a high percentage of eye-movement anomalies have been reported, the aim of this study was to analyze binocular vision in these subjects.

METHODS

A total of 59 participants with MS - 21 with monocular optic neuritis, eleven with binocular optic neuritis, and 27 without optic neuritis - and 26 age-matched controls were enrolled. Binocular vision was analyzed using near point of convergence (NPC), positive and negative fusional vergence for far and near distance, measurement of heterophoria at both distances with cover and modified Thorington tests, and random-dot stereoscopy.

RESULTS

The percentage of subjects with abnormal NPC values was highest in the MS group, followed by the MSONm (MS with optic neuritis in one eye), MSONb (MS with optic neuritis in both eyes), and control groups. MS patients showed an esophoric trend at near distance. Positive fusional vergence showed no significant differences between control and MS groups, but higher variability in recovery was found in MS groups. Negative fusional vergence at near distance showed significant differences between the control group and the two MS groups, with optic neuritis for both break-point and recovery values. A high percentage of patients with MS had alterations on stereopsis.

CONCLUSION

Alterations in binocular vision were present in MS, with divergence at near distance and stereopsis the most affected parameters. Likewise, MS patients with optic neuritis showed worse binocular vision.

Ocular fixation and macular integrity by microperimetry in multiple sclerosis

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Optical coherence tomography angiography findings of multiple sclerosis with or without optic neuritis

Objective: Nowadays, retinal microvascular structures can be investigated using optical coherence tomography angiography (OCTA). We aimed to evaluate the probable vascular changes in the foveal and peripapillary regions of patients with multiple sclerosis (MS).Methods: A total of 20 patients with relapsing remitting multiple sclerosis (RRMS) and 24 healthy controls were recruited in this study. All participants' superficial and deeper retinal and peripapillary layers were evaluated using OCTA after a total ophthalmologic examination.Results: In the superficial plexus, the whole image (49.53 ± 3.9% and 51.83 ± 2.1%, p = 0.009), superior hemisphere (49.44 ± 4.11% and 51.63 ± 2.3%, p = 0.018), inferior hemisphere (49.75 ± 3.9% and 52.03 ± 2.2%, p = 0.012), parafoveal (51.87 ± 3.9% and 53.08 ± 3.46%, p = 0.048) and perifoveal (50.41 ± 3.86% and 52.76 ± 2.1%, p = 0.007) vascular densities were statistically significant lesser in patients with RRMS than in controls. In the optic disc OCTA parameters, the vessel density of the inferior (50.15 ± 6.99% and 53.04 ± 3.63% p = 0.043) and temporal sector (48.09 ± 5.47% and 50.85 ± 5.24%, p = 0.045) were statistically significantly lesser in patients with RRMS than in controls.Conclusion: The reductions in vessel density of the retinal or peripapillary area of patients with RRMS shown in this study should be investigated further to determine whether it is a secondary lesion to optic neuritis (ON) or a primary vasculopathic condition of MS.

Assessment of the optic nerve and its arterial supply by ultrasound imaging in multiple sclerosis patients

Background

Transorbital sonography (TOS) has emerged as a promising assessment tool of the optic nerve and orbital arterial supply in multiple sclerosis (MS) patients.

Objective

To evaluate optic nerve diameter (OND), optic nerve sheath diameter (ONSD), and orbital hemodynamics using TOS in MS patients.

Methods

Forty MS patients and 28 matched healthy controls were included. Thirty-three eyes with previous optic neuritis (ON) and 47 eyes without previous ON of MS patients were examined. All subjects were submitted to assessment of OND, ONSD, and parameters of orbital hemodynamics using orbital ultrasound.

Results

OND and ONSD were smaller in MS eyes with previous ON than in controls. MS eyes with and without previous ON had statistically significant higher peak systolic and mean velocity of posterior ciliary arteries than the control eyes. Orbital blood flow velocities were negatively correlated with the duration of disease and Expanded Disability Status Scale (EDSS). A statistically significant decrease in blood flow velocities of the central retinal artery was detected in secondary progressive MS (SPMS) patients than in relapsing-remitting MS patients (RRMS).

Conclusion

TOS can be used as a feasible tool to detect optic atrophy in MS patients. MS patients may have abnormal retrobulbar hemodynamics compared to healthy controls.

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.

The Topographical Relationship between Visual Field Loss and Peripapillary Retinal Nerve Fibre Layer Thinning Arising from Long-Term Exposure to Vigabatrin

BACKGROUND

The antiepileptic drug vigabatrin is associated with characteristic visual field loss (VAVFL) and thinning of the peripapillary retinal nerve fibre layer (PPRNFL); however, the relationship is equivocal.

OBJECTIVE

The aim of this study was to determine the function-structure relationship associated with long-term exposure to vigabatrin, thereby improving the risk/benefit analysis of the drug.

METHODS

A cross-sectional observational design identified 40 adults who had received long-term vigabatrin for refractory seizures, who had no evidence of co-existing retino-geniculo-cortical visual pathway abnormality, and who had undergone a standardized protocol of perimetry and of optical coherence tomography (OCT) of the PPRNFL. Vigabatrin toxicity was defined as the presence of VAVFL. The function-structure relationship for the superior and inferior retinal quadrants was evaluated by two established models applicable to other optic neuropathies.

RESULTS

The function-structure relationship for each model was consistent with an optic neuropathy. PPRNFL thinning, expressed in micrometres, asymptoted at an equivalent visual field loss of worse than approximately - 10.0 dB, thereby preventing assessment of more substantial thinning. Transformation of the outcomes to retinal ganglion cell soma and axon estimates, respectively, resulted in a linear relationship.

CONCLUSIONS

Functional and structural abnormality is strongly related in individuals with vigabatrin toxicity and no evidence of visual pathway comorbidity, thereby implicating retinal ganglion cell dysfunction. OCT affords a limited measurement range compared with perimetry: severity cannot be directly assessed when the PPRNFL quadrant thickness is less than approximately 65 µm, depending on the tomographer. This limitation can be overcome by transformation of thickness to remaining axons, an outcome requiring input from perimetry.

Multifocal visual evoked potentials and contrast sensitivity correlate with ganglion cell-inner plexiform layer thickness in multiple sclerosis

OBJECTIVE

To examine the relationship between optical coherence tomography (OCT) macular ganglion cell-inner plexiform layer thickness (GCIPLT), peripapillary retinal nerve fiber layer thickness (RNFLT) and visual function in relapsing-remitting multiple sclerosis (RRMS).

METHODS

Cirrus OCT, VERIS 60-sector multifocal visual evoked potential (mfVEP) and Pelli-Robson contrast sensitivity (CS) were obtained for 53 eyes with last optic neuritis (ON) > 6 months and 105 non-ON eyes in 90 patients. One eye (43 ON, 73 non-ON) was used for correlations when both had the same history. Global (G, 60 sectors) and central 5.6° (C, 24 sectors) mfVEP amplitude and latency were calculated as mean logSNR and median latency.

RESULTS

Eyes showing abnormal mfVEP (amplitude or latency) vs OCT (GCIPLT or RNFLT) was 77% vs 69% (p = 0.33) in ON, 45% vs 22% (p < 0.0005) in non-ON. In ON and non-ON, mfVEP measures and CS correlated with GCIPLT and RNFLT (r = -0.24 to 0.78, p = 0.03-0.0001). In ON, mfVEP amplitude (C,G) correlated better with GCIPLT (r = 0.78, 0.76) than RNFLT (r = 0.43, 0.58; p < 0.001, 0.01).

CONCLUSIONS

MfVEP measures and CS correlated well with GCIPLT and RNFLT in ON and non-ON. MfVEP amplitudes were more highly correlated with GCIPLT than RNFLT in ON. MfVEP detected significantly more defects than OCT in non-ON.

SIGNIFICANCE

GCIPLT, mfVEP and CS provide useful measures of optic nerve integrity in RRMS.

Visual field defects and retinal nerve fiber imaging in patients with obstructive sleep apnea syndrome and in healthy controls

Background

To assess the retinal sensitivity in obstructive sleep apnea hypopnea syndrome (OSAHS) patients evaluated with standard automated perimetry (SAP). And to correlate the functional SAP results with structural parameters obtained with optical coherence tomography (OCT).

Methods

This prospective, observational, case-control study consisted of 63 eyes of 63 OSAHS patients (mean age 51.7 ± 12.7 years, best corrected visual acuity ≥20/25, refractive error less than three spherical or two cylindrical diopters, and intraocular pressure < 21 mmHg) who were enrolled and compared with 38 eyes of 38 age-matched controls. Peripapillary retinal nerve fiber layer (RNFL) thickness was measured by Stratus OCT and SAP sensitivities and indices were explored with Humphrey Field Analyzer perimeter. Correlations between functional and structural parameters were calculated, as well as the relationship between ophthalmologic and systemic indices in OSAHS patients.

Results

OSAHS patients showed a significant reduction of the sensitivity for superior visual field division (p = 0.034, t-student test). When dividing the OSAHS group in accordance with the severity of the disease, nasal peripapillary RNFL thickness was significantly lower in severe OSAHS than that in controls and mild-moderate cases (p = 0.031 and p = 0.016 respectively, Mann-Whitney U test). There were no differences between groups for SAP parameters.

We found no correlation between structural and functional variables. The central visual field sensitivity of the SAP revealed a poor Pearson correlation with the apnea-hipopnea index (0.284, p = 0.024).

Conclusions

Retinal sensitivity show minor differences between healthy subjects and OSAHS. Functional deterioration in OSAHS patients is not easy to demonstrate with visual field examination.

Optical Coherence Tomography and Subclinical Optical Neuritis in Longitudinally Extensive Transverse Myelitis

Objective

The aim is to compare the retinal nerve fiber layer (RNFL) thickness of longitudinally extensive transverse myelitis (LETM) eyes without previous optic neuritis with that of healthy control subjects.

Methods

Over 20 LETM eyes and 20 normal control eyes were included in the study and subjected to optical coherence tomography to evaluate and compare the RNFL thickness.

Result

Significant RNFL thinning was observed at 8 o'clock position in LETM eyes as compared to the control eyes (P = 0.038). No significant differences were seen in other RNFL measurements.

Conclusion

Even in the absence of previous optic neuritis LETM can lead to subclinical axonal damage leading to focal RNFL thinning.

Optic Pathway Gliomas in Neurofibromatosis Type 1: An Update: Surveillance, Treatment Indications, and Biomarkers of Vision

Optic pathway gliomas (OPGs) occur in 15%-20% of children with neurofibromatosis type 1 (NF1), leading to visual deficits in fewer than half of these individuals. The goal of chemotherapy is to preserve vision, but vision loss in NF1-associated OPG can be unpredictable. Determining which child would benefit from chemotherapy and, equally important, which child is better observed without treatment can be difficult. Unfortunately, despite frequent imaging and ophthalmologic evaluations, some children experience progressive vision loss before treatment. Indications for chemotherapy usually are based on a comprehensive, quantitative assessment of vision, but reliable vision evaluation can be challenging in young children with NF1-OPG. The ability to identify and predict impending vision loss could potentially improve management decisions and visual outcomes. To address this challenge, ophthalmologic, electrophysiologic, and imaging biomarkers of vision in NF1-OPG have been proposed. We review current recommendations for the surveillance of children at risk for NF1-OPG, outline guidelines for initiating therapy, and describe the utility of proposed biomarkers for vision.

Collaborative SDOCT Segmentation and Analysis Software

Spectral domain optical coherence tomography (SDOCT) is routinely used in the management and diagnosis of a variety of ocular diseases. This imaging modality also finds widespread use in research, where quantitative measurements obtained from the images are used to track disease progression. In recent years, the number of available scanners and imaging protocols grown and there is a distinct absence of a unified tool that is capable of visualizing, segmenting, and analyzing the data. This is especially noteworthy in longitudinal studies, where data from older scanners and/or protocols may need to be analyzed. Here, we present a graphical user interface (GUI) that allows users to visualize and analyze SDOCT images obtained from two commonly used scanners. The retinal surfaces in the scans can be segmented using a previously described method, and the retinal layer thicknesses can be compared to a normative database. If necessary, the segmented surfaces can also be corrected and the changes applied. The interface also allows users to import and export retinal layer thickness data to an SQL database, thereby allowing for the collation of data from a number of collaborating sites.

Recurrent isolated optic neuritis: A study on 22 patients

Background: Isolated relapsing optic neuropathy is a recurrent painful optic nerve inflammation without any sign of other demyelinating diseases such as multiple sclerosis (MS) or neuromyelitis optica (NMO) spectrum disorders, and the attacks are purely responsive to steroid therapy. Methods: Recurrent isolated optic neuritis (RION) was diagnosed in patients who presented with at least two disseminating episodes of optic neuritis, and negative clinical, para-clinical, and radiological features of the demyelinating, infiltrative and vasculitis disorders involving optic nerve. The patients were assigned into two groups, chronic recurrent isolated optic neuritis (CRION) entailing patients with steroid dependent attack of optic neuritis and RION patients without steroid dependent attack of optic neuritis. They were monitored over a median of 4.0 ± 2.5 years. Results: There were 16 women and six men with CRION and RION; with the median age of 31.7 ± 9.8 (29.3 ± 9.7 for women and 37.7 ± 7.7 for men). The women to men ratio was 2.6:1. The mean optic neuritis attack was 2.95 ± 1.32 in total. Eight patients were RION while 14 patients fulfilled CRION criteria and took long term immuno-suppressive drugs. In their follow-up, 4 out of 14 CRION cases (28.5%) showed clinical and concordant para-clinical features of NMO spectrum disorder. The analysis of demographic data showed that the average number of ON attacks in CRION patients (3.79 ± 2.32) was significantly more than the average in patients with RION (2.25 ± 0.46, P = 0.02). Conclusion: CRION is a disease which requires aggressive glucocorticoid and long-term immunosuppressive therapy to restore visual acuity.

Analysis of multiple sclerosis patients with electrophysiological and structural tests

We aimed to analyze the effects of progressive myelin loss and neurodegeneration seen in patients with multiple sclerosis (MS) on visual tract with electrophysiological and structural tests. Fifty-one patients diagnosed with MS in the Neurology Department were followed up in neuro-ophthalmology outpatient clinic irrespective of their visual symptoms, and were included in our study. The patients were classified as the ones with the history of optic neuritis (group II) and ones without the history (group I) of optic neuritis. The data, including clinical presentation, retinal nerve fiber layer thickness (RNFLT) measurements, pattern visual evoked potential (pVEP) and flash electro retino grams (ERG) test results, were recorded. In our study, comparison of pVEP test latencies of groups I and II with each other, and with those of healthy subjects revealed statistically significant differences (p < 0.05). The analysis of rod functions on ERG did not show any significant changes (p > 0.05). However, both groups showed significantly decreased cone b-wave amplitudes, elongation of latencies, and decreased flicker amplitudes on cone and flicker potentials obtained after light adaptation (p < 0.05). There was significant thinning in RNFLT of the both groups when compared to the normal standards. The difference between two groups was statistically significant (p < 0.05). Axon loss is seen in the optic nerve with subclinical or acute optic neuritis in patients with MS. RNFLT analysis and electrophysiological tests are of great importance in diagnosis of MS, as well as to determine progression and to direct neuroprotective therapy in patients diagnosed with MS. Objective analysis methods gain more importance in the diagnosis and follow-up of MS patients, parallel to technological advancements.

Optical Coherence Tomography for the Radiologist

Optical coherence tomography is an imaging technique using low coherence light sources to produce high-resolution cross-sectional images. This article reviews pertinent anatomy and various pathologies causing optic atrophy (eg, compressive, infiltrating, demyelinating) versus optic nerve swelling (from increased intracranial pressure known as papilledema or other optic nerve intrinsic pathologies). On optical coherence tomography, optic atrophy is often associated with reduced average retinal nerve fiber layer thickness, whereas optic nerve swelling is usually associated with increased average retinal nerve fiber layer thickness.

Anatomical and functional retinal changes in multiple sclerosis

AIMS

The aims of this study was to report anatomical changes of the ganglion cell complex (GCC), retinal nerve fiber layer (RNFL) thickness, and macular volume in patients with multiple sclerosis (MS). We also investigated the correlation between anatomical and functional changes in terms of visual acuity and macular sensitivity investigated and visual fields.

METHODS

Prospective comparative study included 105 eyes of 53 consecutive patients. The patients were divided into two groups: group A included 56 eyes of 28 patients with diagnosis of MS; group B involved 49 eyes of 25 healthy patients. The examination included Goldmann tonometry, biomicroscopic and fundus oculi examination, retinography, GCC examination, circumpapillary RNFL (cpRNFL), and macular volume. The functional test included measurement of best-corrected visual acuity (BCVA), visual field, and MP.

RESULTS

MS group showed a significant reduced GCC, cpRNFL, macular volume, BCVA, visual field, and macular sensitivity compared with the control group (P<0.001). This reduction was more representative (P<0.001) in patients with MS complicated by optic neuritis (ON). We found in the MS group a strong correlation between GCC thickness and macular volume (r(2)=0.59, P<0.001) and also between GCC and RNFL thickness (r(2)=0.48, P<0.001). There was also a correlation between macular sensitivity and macular volume reduction (r(2)=0.25, P<0.001) and also between RNFL and macular volume (r(2)=0.43, P<0.001).

CONCLUSIONS

The significant statistical evidence and the strong correlation between anatomical and functional parameters support the use of OCT and MP in the evaluation, treatment, and follow-up of patients diagnosed with MS.

Multiple sclerosis and optic nerve: an analysis of retinal nerve fiber layer thickness and color Doppler imaging parameters

PURPOSE

To compare both retinal nerve fiber layer thickness and orbital color Doppler ultrasonography parameters in patients with multiple sclerosis (MS) versus healthy controls.

METHODS

This is an observational case-control study. Forty eyes from MS patients and twenty eyes from healthy volunteers were examined. Eyes were classified into three groups as group 1, eyes from MS patients with previous optic neuritis (n=20); group 2, eyes from MS patients without previous optic neuritis (n=20); and group 3, eyes from healthy controls (n=20). Following complete ophthalmologic examination and retinal nerve fiber layer thickness measurement for each group, blood flow velocities of posterior ciliary arteries, central retinal artery, ophthalmic artery, and superior ophthalmic vein were measured. Pourcelot index (resistive index), an indicator of peripheral vascular resistance, was also calculated. The statistical assessment was performed with the assistance of Pearson's Chi-square test, Mann-Whitney U-test, Kruskal-Wallis test, and Spearman's correlation test.

RESULTS

The studied eyes exposed similar values in terms of intraocular pressure and central corneal thickness, implying no evidence in favor of glaucoma. All nerve fiber layer thickness values, except superior nasal quadrants, in group 1 were found to be significantly thinner than groups 2 and 3. Blood flow velocity and mean resistivity index parameters were similar in all the groups.

CONCLUSIONS

In MS patients, especially with previous optic neuritis, diminished retinal nerve fiber layer thickness was observed. Contrary to several studies in the current literature, no evidence supporting potential vascular origin of ocular involvement in MS was found.

Evaluation of contrast sensitivity measurements after retrobulbar optic neuritis in Multiple Sclerosis

Background

The evaluation of contrast sensitivity is an important additional examination that allows the physician to achieve the full picture of a patient's quality of vision. In low-contrast conditions, more discrete visual dysfunctions may be revealed, which could be overlooked in high-contrast tests.

Methods

The examined group consisted of 33 eyes of 27 patients with multiple sclerosis. The study included patients with full or almost full visual acuity, without visual field defects or any other ophthalmic condition, and who had never undergone any ocular surgery or trauma. The reference group consisted of 49 eyes of 37 patients. This group included healthy subjects with full visual acuity. Contrast sensitivity was examined with a Functional Vision Analyzer™ device in photopic conditions (with and without glare) and in mesopic conditions (with and without glare).

Results

In patients with multiple sclerosis who had experienced optic neuritis, contrast sensitivity was found to be significantly reduced in all spatial frequencies in both mesopic and photopic conditions (with and without glare).

Conclusions

Contrast sensitivity in patients with multiple sclerosis who have also had optic neuritis is significantly reduced. This may explain patients' complaints regarding their quality of vision, despite good visual acuity. Contrastometry is a useful basis for further examination, providing additional information regarding a patient's quality of vision.

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.

Functional outcome measures for NF1-associated optic pathway glioma clinical trials

OBJECTIVE

The goal of the Response Evaluation in Neurofibromatosis and Schwannomatosis Visual Outcomes Committee is to define the best functional outcome measures for future neurofibromatosis type 1 (NF1)-associated optic pathway glioma (OPG) clinical trials.

METHODS

The committee considered the components of vision, other ophthalmologic parameters affected by OPG, potential biomarkers of visual function, and quality of life measures to arrive at consensus-based, evidence-driven recommendations for objective and measurable functional endpoints for OPG trials.

RESULTS

Visual acuity (VA) assessments using consistent quantitative testing methods are recommended as the main functional outcome measure for NF1-OPG clinical trials. Teller acuity cards are recommended for use as the primary VA endpoint, and HOTV as a secondary endpoint once subjects are old enough to complete it. The optic disc should be assessed for pallor, as this appears to be a contributory variable that may affect the interpretation of VA change over time. Given the importance of capturing patient-reported outcomes in clinical trials, evaluating visual quality of life using the Children's Visual Function Questionnaire as a secondary endpoint is also proposed.

CONCLUSIONS

The use of these key functional endpoints will be essential for evaluating the efficacy of future OPG clinical trials.

Optical coherence tomography versus visual evoked potentials in detecting subclinical visual impairment in multiple sclerosis

RATIONALE

Visual impairment is one of the most common clinical manifestations of multiple sclerosis (MS). Some multiple sclerosis patients complain of poor vision although the Snellen visual acuity is 20/20. This study reveals that sensitive measurements like visual evoked potential (VEP) and optical coherence tomography (OCT) can evidence subclinical disturbances of visual pathway. These methods examine the relation between the visual function (VEP) and retinal nerve fiber layer (RNFL) thickness, as a structural biomarker for axonal loss in patients with multiple sclerosis (MS). The findings in this study indicate the utility of combining structural and functional testing in clinical research on patients with MS.

PURPOSE

To detect visual impairment in a population of visually asymptomatic patients affected by clinically definite multiple sclerosis (MS) and to compare the utility of optical coherence tomography (OCT) versus visual evoked potentials (VEP).

MATERIAL AND METHODS

Fourteen patients (28 eyes) affected by clinically definite MS, without a history of optic neuritis and asymptomatic for visual disturbances, were initially fully examined (visual acuity, ocular fundus, biomicroscopy) from an ophthalmic point of view and then measured by OCT (RNFL thickness) and VEP. Patients with a history of glaucoma or other retinal or optic nerve disease were excluded.

RESULTS

Of fourteen patients (28 eyes), VEP was abnormal in 11 cases (78,57%) and OCT (RNFL thickness) was abnormal in 5 cases (35,71%), while 3 patients had no abnormalities on neither tests.

CONCLUSIONS

Optical coherence tomography (OCT) is less sensitive than visual evoked potentials (VEPs) in detecting visual subclinical impairment in patients with multiple sclerosis (MS). VEP remains the preferred test for the detection of clinical and subclinical optic neuritis. OCT may provide complementary information to VEP in cases with clinical definite MS and represent a valuable research instrument for the study of optic nerve disease in populations. The findings in this study reveal the utility of combining structural and functional testing in clinical research on patients with MS.

Electropysiologic evaluation of the visual pathway in patients with multiple sclerosis

PURPOSE

To evaluate the ability of visual evoked potentials and pattern electroretinograms (PERG) to detect subclinical axonal damage in patients during the early diagnostic stage of multiple sclerosis (MS). The authors also compared the ability of optical coherence tomography (OCT), PERG, and visual evoked potentials to detect axonal loss in MS patients and correlated the functional and structural properties of the retinal nerve fiber layer.

METHODS

Two hundred twenty-eight eyes of 114 subjects (57 MS patients and 57 age- and sex-matched healthy controls) were included. The visual pathway was evaluated based on functional and structural assessments. All patients underwent a complete ophthalmic examination that included assessment of visual acuity, ocular motility, intraocular pressure, visual field, papillary morphology, OCT, visual evoked potentials, and PERG.

RESULTS

Visual evoked potentials (P100 latency and amplitude), PERG (N95 amplitude and N95/P50 ratio), and OCT parameters differed significantly between MS patients and healthy subjects. Moderate significant correlations were found between visual evoked potentials or PERG parameters and OCT measurements.

CONCLUSIONS

Axonal damage in ganglion cells of the visual pathway can be detected based on structural measures provided by OCT in MS patients and by the N95 component and N95/P50 index of PERG, thus providing good correlation between function and structure.

Visual pathway abnormalities were found in most multiple sclerosis patients despite history of previous optic neuritis

OBJECTIVE

It was to investigate visual field (VF) abnormalities in a group of multiple sclerosis (MS) patients in the remission phase and the presence of magnetic resonance imaging (MRI) lesions in the optic radiations.

METHODS

VF was assessed in 60 participants (age range 20-51 years): 35 relapsing-remitting MS patients [20 optic neuritis (+), 15 optic neuritis (-)] and 25 controls. MRI (3-Tesla) was obtained in all patients.

RESULTS

Visual parameters were abnormal in MS patients as compared to controls. The majority of VF defects were diffuse. All patients except one had posterior visual pathways lesions. No significant difference in lesion number, length and distribution was noted between patients with and without history of optic neuritis. One patient presented homonymous hemianopsia.

CONCLUSION

Posterior visual pathway abnormalities were found in most MS patients despite history of previous optic neuritis.

Predictive value of 1 month retinal nerve fiber layer thinning for deficits at 6 months after acute optic neuritis

BACKGROUND

Retinal nerve fiber layer (RNFL) loss occurs with multiple sclerosis and after optic neuritis. Vision or RNFL changes at presentation of optic neuritis are not predictive of outcome, but vision loss at 1 month correlates with vision deficits at 6 months. We hypothesized that RFNL thinning at 1 month would predict RNFL loss at 6 months.

METHODS

We prospectively studied the RNFL by optical coherence tomography (OCT) and scanning laser polarimetry (SLP), and determined the threshold field mean deviation, in 25 subjects with acute optic neuritis over a 6-month period. RNFL values, including the amount of thinning at 1-month, were correlated with 6-month outcome.

RESULTS

Baseline visual performance and RNFL values were similar for eyes grouped by 1 month RNFL thinning. Eyes with 1 month RNFL thinning had greater and significant RNFL thinning at 6 months, for all quadrants by OCT and for the nasal and inferior quadrants by SLP. RNFL thinning by OCT and SLP at 1 month correlated with 6-month OCT (r = 0.58; p = 0.006) and SLP (r = 0.59; p = 0.002) RNFL thinning, respectively.

CONCLUSION

Early RNFL loss at 1 month was predictive of the RNFL thinning at 6 months, which corroborated the importance of the 1-month time point for predicting the outcome of an optic neuritis attack.

Slit-lamp-adapted ultra-high resolution OCT for imaging the posterior segment of the eye

The purpose of this study was to determine the feasibility of a slit-lamp-adapted ultra-high resolution optical coherence tomography device with improved image resolution for imaging the retinal nerve fiber layer. The authors described the system configuration, build-up, and test results of a small sample of human subjects. The comparison with a commercially available device was also included.

The photopic negative response of the flash electroretinogram in multiple sclerosis

PURPOSE

To use the photopic electroretinogram (ERG) to evaluate retinal function in eyes of multiple sclerosis (MS) patients with and without a history of optic neuritis (ON) and to compare the functional and structural status of the inner retina.

METHODS

Full-field ERG responses to brief red flashes (0.04-2.8 cd · s/m²) on a rod-saturating blue background were recorded from 51 MS patients and 33 age-matched control subjects. In patients, perimetry was performed and peripapillary retinal nerve fiber layer thickness (RNFLT) was assessed by optical coherence tomography (OCT) and scanning laser polarimetry (SLP). MS eyes were separated into groups: "ON >6" months (n = 25), "ON <6" months (n = 29), and "no ON" (n = 33) based on positive or negative history of ON and time since the last episode. Thirteen ON<6 eyes were re-evaluated 1 year later.

RESULTS

PhNR amplitudes were lower in ON>6, ON<6, and no-ON eyes (mean ± SD, 17.3 ± 7.6, 16.0 ± 6.5, and 23.8 ± 9.3 μV, respectively), than in control eyes (29.8 ± 6.5 μV; P < 0.001) for a standard stimulus of 1.42 cd · s/m²; a- and b-wave amplitudes were unaffected. PhNR amplitudes correlated with visual fields mean deviation (MD) in ON>6 (r² = 0.43; P < 0.001) and no-ON eyes (r² = 0.10; P < 0.05), with similar results for weaker stimuli. PhNR amplitudes correlated with RNFLT in ON>6 eyes: OCT (r² = 0.52; P < 0.0001) and SLP (r² = 0.51; P < 0.01); and in no-ON eyes, OCT (r² = 0.21; P < 0.01) and SLP (r² = 0.17; P < 0.05). ON<6 amplitudes did not correlate significantly with other measures, but increased after 1 year by 5.1 ± 3.1 μV (P < 0.001), visual fields MD increased by 1.8 ± 2.3 dB (P < 0.05), and RNFL loss persisted.

CONCLUSIONS

Photopic ERG PhNR amplitudes in MS patients are significantly reduced in eyes with and without a history of ON.

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.

Vision in multiple sclerosis: the story, structure-function correlations, and models for neuroprotection

Visual dysfunction is one of the most common clinical manifestations of multiple sclerosis (MS). Just over a decade ago, MS clinical trials did not include visual outcomes, but experts recognized the need for more sensitive measures of visual function. Low-contrast letter acuity emerged as the leading candidate to measure visual disability in MS, and subsequent studies found low-contrast acuity testing to correlate well with brain MRI lesion burden, visual-evoked potentials, quality of life (QOL), and retinal nerve fiber layer (RNFL) loss, as measured by optical coherence tomography (OCT). OCT in MS has allowed for assessment of structure-function correlations that make the anterior visual pathway and acute optic neuritis (ON) ideal models for testing novel agents for neuroprotection and repair. New therapies that reduce axonal loss by neuroprotective or myelin repair mechanisms can now be assessed noninvasively by OCT and coupled with visual function data. Based on OCT studies in MS, RNFL thickness is reduced significantly among patients (92 μm) vs controls (105 μm) and is particularly reduced in MS eyes with a history of ON (85 μm). Worsening of visual function by a clinically significant ≥ 7 letters or approximately 1.5 lines for low-contrast acuity is associated with approximately 4.5 μm reductions in RNFL thickness in MS eyes. Longitudinal studies of OCT have also shown RNFL axonal loss over time that occurs even in the absence of acute ON and that correlates with clinically meaningful worsening of vision and QOL, even in patients with benign MS. The latest OCT investigations involve high-resolution spectral-domain (SD) OCT with segmentation and measurement of specific retinal layers using computerized algorithms. These methods allow quantitation of ganglion cell (neuronal) layer loss and axonal degeneration in MS in vivo. In this review, we examine the data from these studies and ongoing trials that highlight the entity of ON as a model to investigate neuroprotection and neurorepair. In doing so, we also present representative group data from studies that have examined visual function, OCT measures, and QOL scales in patients with MS and ON and disease-free controls. These data, and those from recent meta-analyses, may be used to provide reference values for the development of clinical trial protocols.

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.

Interocular symmetry of abnormal multifocal electroretinograms in adolescents with diabetes and no retinopathy

PURPOSE

To investigate, in adolescents with type 1 diabetes and no retinopathy, the spatial correspondence between abnormal multifocal electroretinogram (mfERG) responses in the two eyes.

METHODS

mfERG and fundus photographs were measured in both eyes of 68 adolescents with type 1 diabetes and no retinopathy (13 to 19 years old; best corrected visual acuity ≥ 20/20), and 30 age-matched controls. The mfERG stimulus was comprised of 103 hexagons, and subtended 45°. mfERG implicit times (IT) and amplitudes (AMP) were derived. Fifteen patients for IT, and five for AMP with at least one eye defined as abnormal (six or more locations with abnormal Z-scores; P < 0.03) were analyzed.

RESULTS

Nasal retina had significantly more abnormal IT locations compared with temporal retina (P = 0.015), and the opposite was true with regard to abnormal AMP (P < 0.001). The proportion of abnormal responses in the superior retina was not significantly different from that in the inferior retina (P > 0.1 for IT and AMP). Interocular correspondence of locations with abnormal mfERG IT was significant for all 15 patients (P values <0.0001-0.012), and agreement between eyes was 68% to 94% (AC1 agreement coefficient: 0.48-0.94). Overall interocular correspondence was also significant (P < 0.0002), with 86% agreement (AC1 = 0.76). Overall interocular correspondence of locations with abnormal mfERG AMP was also significant (P < 0.0002).

CONCLUSIONS

Interocular spatial correspondence of abnormal mfERG responses exists in adolescents with type 1 diabetes and no retinopathy. This is most apparent for IT abnormalities. This correspondence could be used in clinical trials, and raises the possibility of initiating treatment in both eyes at early disease stages as new topical treatments emerge.

Understanding and interpreting vision safety issues with vigabatrin therapy

Vigabatrin is an irreversible inhibitor of γ-aminobutyric acid (GABA) transaminase. It is effective as adjunctive therapy for adult patients with refractory complex partial seizures (rCPS) who have inadequately responded to several alternative treatments and as monotherapy for children aged 1 month to 2 years with infantile spasms. The well-documented safety profile of vigabatrin includes risk of retinopathy characterized by irreversible, bilateral, concentric peripheral visual field constriction. Thus, monitoring of visual function to understand the occurrence and manage the potential consequences of peripheral visual field defects (pVFDs) is now required for all patients who receive vigabatrin. However, screening for pVFDs for patients with epilepsy was conducted only after the association between vigabatrin and pVFDs was established. We examined the potential association between pVFDs and epilepsy in vigabatrin-naïve patients and attempted to identify confounding factors (e.g., concomitant medications, method of vision assessment) to more accurately delineate the prevalence of pVFDs directly associated with vigabatrin. Results of a prospective cohort study as well as several case series and case reports suggest that bilateral visual field constriction is not restricted to patients exposed to vigabatrin but has also been detected, although much less frequently, in vigabatrin-naïve patients with epilepsy, including those who received treatment with other GABAergic antiepileptic therapy. We also reviewed published data suggesting an association between vigabatrin-associated retinal toxicity and taurine deficiency, as well as the potential role of taurine in the prevention of this retinopathy.

Reduced retinal nerve fiber layer and macular thickness in patients with multiple sclerosis with no history of optic neuritis identified by the use of spectral domain high-definition optical coherence tomography

Multiple sclerosis (MS) is a chronic immune-mediated disease of the central nervous system (CNS), with both inflammatory and degenerative components. The visual system is frequently involved, often in the form of visual loss from optic neuritis (ON). Retinal nerve fiber layer (RNFL) loss has been demonstrated in individuals with MS, not only in those with previous ON but also in absence of historical evidence of previous acute inflammation/demyelination of the optic nerve. Peripapillary RNFL measurements of all quadrants, central macular thickness, and average macular thickness were performed in 32 eyes of healthy volunteers and 60 eyes of individuals with a diagnosis of relapsing remitting MS using high definition spectral domain optical coherence tomography (HD-OCT). Both the Macular Cube 512 × 128 scan and RNFL measurement by the Optic Disc Cube 200 × 200 protocol were performed on all eyes. Eyes of individuals with MS with no previous ON had significantly decreased overall RNFL thickness (89.1 μm) compared to controls (98.0 μm) (p < 0.05). MS mainly affected the temporal quadrant (56.6 μm versus [vs.] 67.8 μm) (p < 0.05), and inferior quadrant (117.9 μm vs. 132.1 μm) (p < 0.05), respectively. Also, the patients with MS demonstrated significantly decreased average macular thickness (280 μm) compared to the control group (287 μm) (p < 0.05). A significant correlation between RNFL and average macular thickness was also found in eyes of patients with MS (r = 0.69, p < 0.01). HD-OCT is a quick, inexpensive and promising tool to detect subclinical changes in RNFL and macular thickness in individuals with MS. Longitudinal studies should be encouraged to examine disease progression over time in individuals with MS.

Comparison of retinal nerve fibre layer thickness with visual evoked potential and visual field in patients with multiple sclerosis

BACKGROUND

To evaluate retinal nerve fibre layer thickness and to compare results with visual evoked potentials and visual field in patients with multiple sclerosis.

DESIGN

A prospective, case-control study, university hospital setting.

PARTICIPANTS

Seventy-three eyes of 37 multiple sclerosis patients and 74 eyes of 37 healthy subjects.

METHODS

All patients underwent a complete neurological and ophthalmological examination and peri-papillary retinal nerve fibre layer thickness was evaluated using scanning laser polarimetry (GDx). Furthermore, visual evoked potential and visual field testing were performed.

MAIN OUTCOME MEASURES

The χ(2) test, Student's t-test, Mann-Whitney U-test and Pearson's correlation coefficient analysis of the GDx, visual evoked potential and visual field testing parameters.

RESULTS

GDx measurements showed significantly more retinal nerve fibre layer damage in the patients than in the control groups. Comparison of the GDx parameters between patients with optic neuritis and non-optic neuritis demonstrated a statistically significant difference in symmetry (P = 0.046) and superior/nasal parameters (P = 0.009). A correlation was found between the number, superior and inferior ratio parameters, and P100 amplitude obtained with visual evoked potential in patients with non-optic neuritis. Additionally, there was a correlation between the number, inferior ratio and superior/nasal parameters, and the mean deviation of visual field in the non-optic neuritis group.

CONCLUSIONS

For retinal nerve fibre layer thickness measurements in multiple sclerosis patients, the GDx, along with other techniques, such as visual evoked potential, can be used as a diagnostic and follow-up criterion, particularly in patients without optic neuritis.

Anatomic and functional correlation of frequency-doubling technology perimetry (FDTP) in multiple sclerosis

To study the correlation between the results of frequency-doubling technology perimetry (FDTP), visual function (visual acuity, contrast vision, standard automated perimetry (SAP)) and the thickness of the retinal nerve fiber layer (RNFL) throughout the course of multiple sclerosis (MS). Sixty-six eyes of thirty-three patients suffering from MS were chosen. Thirty-five eyes had a previous history of optic neuritis (ON group) and thirty-one eyes had no previous history of optic neuritis (non-ON group). The FDTP was performed with the N-30 screening program. Visual acuity was determined with the Snellen scale and the ETDRS (Early Treatment Diabetic Retinopathy Study) scale, the contrast vision with the Pelli-Robson and Sloan tests and the SAP with the Humphrey 750 perimeter. The thickness of the RNFL was measured using the STRATUS OCT™ optical coherence tomography (OCT). The visual field FDTP was divided into three sectors corresponding to the three SAP sectors and to the three RNFL quadrants of the OCT. The FDTP was significantly correlated (P<0.0001) to the contrast vision and to the SAP results (mean deviation (MD) and the different sectors among themselves). In the ON group, the MD FDTP was significantly correlated to the average RNFL thickness (r=0.44, P=0.0091). A decrease of 5 decibels (dB) of the MD FDTP corresponded to a decrease of 11.7 μm of the average RNFL thickness (Y=2.34×X+87.5). The strong correlation with SAP and RNFL confirms the value of FDTP in assessing optic nerve damage throughout the course of MS.

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.