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Concept: Nerve fiber layer

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The parapapillary gamma zone has recently been defined as the parapapillary region free of Bruch’s membrane. Although it has been reported the presence of defects in peripapillary gamma zone, hitherto undescribed is the herniation of the retinal nerve fiver layer tissue into the peripapillary gamma zone defect with the resulting localized defects in the retinal nerve fiber layer.

Concepts: Eye, Bruch's membrane, Nerve fiber layer

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To compare the diagnostic ability of the ganglion cell analysis (GCA) and retinal nerve fiber layer (RNFL) protocol on optical coherence tomography (OCT), to diagnose preperimetric glaucoma.

Concepts: Nervous system, Optics, Diagnosis, Greek loanwords, Retina, Optical coherence tomography, Nerve fiber layer

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Retinal cell apoptosis occurs in many ocular neurodegenerative conditions including glaucoma-the major cause of irreversible blindness worldwide. Using a new imaging technique that we have called DARC (detection of apoptosing retinal cells), which until now has only been demonstrated in animal models, we assessed if annexin 5 labelled with fluorescent dye DY-776 (ANX776) could be used safely in humans to identify retinal cell apoptosis. Eight patients with glaucomatous neurodegeneration and evidence of progressive disease, and eight healthy subjects were randomly assigned to intravenous ANX776 doses of 0.1, 0.2, 0.4 and 0.5 mg in an open-label, phase 1 clinical trial. In addition to assessing the safety, tolerability and pharmacokinetics of ANX776, the study aimed to explore whether DARC could successfully visualize individual retinal cell apoptosis in vivo in humans, with the DARC count defined as the total number of unique ANX776-labelled spots. DARC enabled retinal cell apoptosis to be identified in the human retina using ANX776. Single ANX776-labelled cells were visualized in a dose-dependent pattern (P < 0.001) up to 6 h after injection. The DARC count was significantly higher (2.37-fold, 95% confidence interval: 1.4-4.03, P = 0.003) in glaucoma patients compared to healthy controls, and was significantly (P = 0.045) greater in patients who later showed increasing rates of disease progression, based on either optic disc, retinal nerve fibre layer or visual field parameters. Additionally, the DARC count significantly correlated with decreased central corneal thickness (Spearman's R = -0.68, P = 0.006) and increased cup-disc ratios (Spearman's R = 0.47, P = 0.038) in glaucoma patients and with increased age (Spearman's R = 0.77, P = 0.001) in healthy controls. Finally, ANX776 was found to be safe and well-tolerated with no serious adverse events, and a short half-life (10-36 min). This proof-of-concept study demonstrates that retinal cell apoptosis can be identified in the human retina with increased levels of activity in glaucomatous neurodegenerative disease. To our knowledge, this is the first time individual neuronal apoptosis has been visualized in vivo in humans and is the first demonstration of detection of individual apoptotic cells in a neurodegenerative disease. Furthermore, our results suggest the level of apoptosis ('DARC count') is predictive of disease activity, indicating the potential of DARC as a surrogate marker. Although further trials are clearly needed, this study validates experimental findings supporting the use of DARC as a method of detection and monitoring of patients with glaucomatous neurodegeneration, where retinal ganglion cell apoptosis is an established process and where there is a real need for tools to non-invasively assess treatment efficacy.

Concepts: Nervous system, Neuron, Apoptosis, Action potential, Retina, Optic nerve, Ganglion cell, Nerve fiber layer

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OBJECTIVE: To determine the effect of clinical and radiologic disease activity on the rate of thinning of the ganglion cell/inner plexiform (GCIP) layer and the retinal nerve fiber layer in patients with multiple sclerosis (MS) using optical coherence tomography (OCT). METHODS: One hundred sixty-four patients with MS and 59 healthy controls underwent spectral-domain OCT scans every 6 months for a mean follow-up period of 21.1 months. Baseline and annual contrast-enhanced brain MRIs were performed. Patients who developed optic neuritis during follow-up were excluded from analysis. RESULTS: Patients with the following features of disease activity during follow-up had faster rates of annualized GCIP thinning: relapses (42% faster, p = 0.007), new gadolinium-enhancing lesions (54% faster, p < 0.001), and new T2 lesions (36% faster, p = 0.02). Annual GCIP thinning was 37% faster in those with disability progression during follow-up, and 43% faster in those with disease duration <5 years vs >5 years (p = 0.003). Annual rates of GCIP thinning were highest in patients exhibiting combinations of new gadolinium-enhancing lesions, new T2 lesions, and disease duration <5 years (70% faster in patients with vs without all 3 characteristics, p < 0.001). CONCLUSIONS: MS patients with clinical and/or radiologic nonocular disease activity, particularly early in the disease course, exhibit accelerated GCIP thinning. Our findings suggest that retinal changes in MS reflect global CNS processes, and that OCT-derived GCIP thickness measures may have utility as an outcome measure for assessing neuroprotective agents, particularly in early, active MS.

Concepts: Nervous system, Optics, Magnetic resonance imaging, Multiple sclerosis, Retina, Optical coherence tomography, Optic nerve, Nerve fiber layer

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Background and purpose:  Optic nerve involvement is frequent in mitochondrial disease, and retinal abnormalities are described in Parkinson’s disease (PD). Methods:  We evaluated retinal nerve fiber layer (RNFL) thickness by optical coherence tomography in 43 patients with PD and in 86 age-matched controls. We considered separately the eyes ipsilateral and contralateral to the most affected body side in patients with PD. ancova analysis, Pearson test, and multiple regression analysis were used (P < 0.05). Results:  Patients with PD showed significantly thinner temporal RNFL thickness compared to controls (P = 0.004), more evident in the eye contralateral to the most affected body side. Average RNFL thickness significantly correlated with age in both controls and patients with PD (P-values ranging from 0.001 to 0.019), whereas in patients with PD RNFL thickness did not correlate with clinical variables. Conclusions:  Our study reveals a loss of retinal nerve fibers in the temporal quadrant in PD, which is typically susceptible in mitochondrial optic neuropathies.

Concepts: Nervous system, Regression analysis, Optics, Parkinson's disease, Retina, Eye, Axon, Nerve fiber layer

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OBJECTIVE: Neuroretinal rim assessment based on the clinical optic disc margin (DM) lacks a sound anatomic basis for 2 reasons: (1) The DM is not reliable as the outer border of rim tissue because of clinically and photographically invisible extensions of Bruch’s membrane (BM) inside the DM and (2) nonaccountability of rim tissue orientation in the optic nerve head (ONH). The BM opening-minimum rim width (BMO-MRW) is a parameter that quantifies the rim from its true anatomic outer border, BMO, and accounts for its variable orientation. We report the diagnostic capability of BMO-MRW. DESIGN: Case control. PARTICIPANTS: Patients with open-angle glaucoma (n = 107) and healthy controls (n = 48). METHODS: Spectral-domain optical coherence tomography (SD-OCT) with 24 radial and 1 circumpapillary B-scans, centered on the ONH, and confocal scanning laser tomography (CSLT) were performed. The internal limiting membrane (ILM) and BMO were manually segmented in each radial B-scan. Three SD-OCT parameters were computed globally and sectorally: (1) circumpapillary retinal nerve fiber layer thickness (RNFLT); (2) BMO-horizontal rim width (BMO-HRW), the distance between BMO and ILM in the BMO reference plane; and (3) BMO-MRW, the minimum distance between BMO and ILM. Moorfields Regression Analysis (MRA) with CLST was performed globally and sectorally to yield MRA1 and MRA2, where “borderline” was classified as normal and abnormal, respectively. MAIN OUTCOME MEASURES: Sensitivity, specificity, and likelihood ratios (LRs) for positive and negative test results (LR+/LR-). RESULTS: The median (interquartile range) age and mean deviation of patients and controls were 69.9 (64.3-76.9) and 65.0 (58.1-74.3) years and -3.92 (-7.87 to -1.62) and 0.33 (-0.32 to 0.98) dB, respectively. Globally, the BMO-MRW yielded better diagnostic performance than the other parameters. At 95% specificity, the sensitivity of RNFLT, BMO-HRW, and BMO-MRW was 70%, 51%, and 81%, respectively. The corresponding LR+/LR- was 14.0/0.3, 10.2/0.5, and 16.2/0.2. Sectorally, at 95% specificity, the sensitivity of RNFLT ranged from 31% to 59%, of BMO-HRW ranged from 35% to 64%, and of BMO-MRW ranged from 54% to 79%. Globally and in all sectors, BMO-MRW performed better than MRA1 or MRA2. CONCLUSIONS: The higher sensitivity at 95% specificity in early glaucoma of BMO-MRW compared with current BMO methods is significant, indicating a new structural marker for the detection and risk profiling of glaucoma. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found after the references.

Concepts: Optics, Median, Retina, Eye, Glaucoma, Optic nerve, Blind spot, Nerve fiber layer

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Purpose: To evaluate differences between the retinal nerve fiber layer (RNFL) thickness and RNFL + ganglion cell layer (GCL) thickness in patients affected by Alzheimer’s disease (AD) and healthy patients using spectral-domain optical coherence tomography (SD-OCT). Methods: This was a case-control prospective study. Twenty-one AD patients and 21 healthy subjects underwent neurological examination, clock drawing test (CDT), mini mental state examination (MMSE) and comprehensive ophthalmic evaluation with visual acuity. SD-OCT examination was performed using Spectralis (Heidelberg Engineering, Heidelberg, Germany), and RTVue-100 (Optovue Inc., Freemont, CA, USA). A RNFL thickness map was obtained using the Spectralis volume protocol with 19 lines on the 30° field centered on the macula. On each B-scan, the outer RNFL limit was manually set. Statistical analysis was performed to assess interoperator RNFL evaluation thickness. A RNFL + GCL thickness map was obtained using the RTVue-100 MM6 protocol. Maps were divided in the 9 ETDRS subfields and each map value in every area was evaluated. A single eye from each patient was randomly chosen to perform the analysis. Differences between AD and healthy subjects were assessed. Results: The two study groups were age and sex matched. MMSE results were 19.9 +- 3.1 and 27.9 +- 1.3, respectively (p < 0.001). There was good agreement in the manual delimitation of the RNFL layer. There was a significant difference in the thickness of both the RNFL and the RNFL+GCL in all examined fields. For example in the inferior internal subfield, the RNFL thickness was 28.1 μm +- 3.1 μm for AD patients and 32.6 μm +- 3.8 μm for healthy subjects (p < 0.001). Conclusion: These results indicate that RNFL and RNFL+GCL thickness measurements are reduced in AD patients compared to healthy subjects. This finding may represent a useful element for the diagnosis and follow up of this pathology.

Concepts: Alzheimer's disease, Nervous system, Optics, Assessment, Retina, Eye, Mental status examination, Nerve fiber layer

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PurposeTo investigate longitudinal changes in peripapillary retinal nerve fiber layer (RNFL) thickness in patients with retinitis pigmentosa (RP).MethodsWe re-examined 103 RP patients whose RNFL thickness was previously examined and reported. RNFL thickness was measured using Stratus optical coherence tomography and was compared with the previous measurements. The results were also compared with that of previously reported normal subjects. Association between the decrease rate and visual acuity, and visual field was also investigated.ResultsThe mean follow-up period was 56.9 months. After excluding the patients in whom RNFL images were of poor quality, 88 patients were eventually analyzed. The average RNFL thickness decreased from 105.8 to 98.2 μm during the period, with the average rate of decrease being 1.6 μm/year. The decrease in RNFL was more evident in superior and inferior sectors. Cross-sectional linear regression analysis also revealed an age-dependent decrease in RNFL, with the slower rate of decrease being 0.94 μm/year. The decrease in RNFL thickness was significantly faster than that reported in normal subjects. The decrease rate was not associated with visual functions.ConclusionAge-dependent RNFL thinning occurs at a faster rate in RP patients as compared with that in normal subjects. The result supports the notion that pathologic changes involve inner retina as well as outer retina in eyes with RP. Considering the discrepancy in the rate of RNFL thinning estimated from trend analysis and longitudinal measurement, care should be taken when interpreting the result of cross-sectional analysis.Eye advance online publication, 22 March 2013; doi:10.1038/eye.2013.34.

Concepts: Regression analysis, Linear regression, Measurement, Retina, Eye, Retinitis pigmentosa, Optic nerve, Nerve fiber layer

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Abstract Purpose: To evaluate the early retinal changes and its reflection on the visual field examination in chronic hepatitis B (CHB) patients using pegylated interferon-α (PEGIFN-α) monotherapy. Patients and methods: Thirty eyes of fifteen patients with CHB were examined prospectively for changes in the fundus examination and visual field examination (both Humphrey Perimetry and Frequency Doubling Perimetry). The patients were examined before and in 3 months intervals after starting the PEGIFN-α treatment. The changes in the fundus examination were noted and the visual field examinations, retinal nerve fiber thickness, Schirmer scores and color vision before and at 3 months of the treatment were compared. The statistical evaluation was performed with paired-t test, using SPSS 16.0 Inc. (Chicago, IL). Results: The mean age of the 15 patients (seven male, eight female) was 52.5 ± 12.4 years. There was no significant retinal change in none of the patients. Neither the visual field examination with Humphrey Field Analyzer nor the Frequency Doubling Perimetry results has demonstrated any significant change during 3 months follow-up. There was a statistically significant increase in the retinal nerve fiber layer (RNFL) thickness; while Schirmer test scores for dry eye assessment was significantly decreased. Conclusion: PEGIFN-α monotherapy, which is used for treatment of CHB, may cause some changes in the thickness of RNFL that may necessitate the close follow-up for further morphological changes of the optic disc in these patients.

Concepts: Statistics, Hepatitis, Retina, Eye, Hepatitis B, Ophthalmology, Optic nerve, Nerve fiber layer

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Purpose:  To investigate the clinical value of assessment of peripapillary retinal nerve fibre layer (RNFL) thickness with OCT in addition to the evaluation of retinal function measured by full-field electroretinography (ff-ERG) in patients with suspected vigabatrin (VGB)-attributed visual field defects. Methods:  Visual fields from adult patients in our clinical follow-up program for VGB medication were analysed. Twelve patients with suspected VGB-attributed visual field defects were selected for the study. They were re-examined with computerized kinetic perimetry, ff-ERG and OCT (2D circle scan). Results:  Constricted visual fields were found in all patients. Comparative analysis of ff-ERG parameters showed reduced b-wave amplitudes for the isolated and the combined rod and cone responses (p < 0.0001). The a-wave, reflecting photoreceptor activity, was reduced (p = 0.001), as well as the summed amplitude of oscillatory potentials (p = 0.029), corresponding to inner retinal function. OCT measurements demonstrated attenuation of the RNFL in nine of 12 patients, most frequently superiorly and/or inferiorly. No temporal attenuation was found. Significant positive correlations were found between the total averaged RNFL thickness, superior and inferior RNFL thickness and reduced ff-ERG parameters. Positive correlations were also found between RNFL thickness and isopter areas. Conclusion:  OCT measurements can detect attenuation of the RNFL in patients exposed to VGB medication. RNFL thickness correlates with reduced ff-ERG parameters and isopter areas of constricted visual fields, indicating that VGB is retino-toxic on several levels, from photoreceptors to ganglion cells. The study also supports previous studies, suggesting that OCT measurement of the RNFL thickness may be of clinical value in monitoring patients on vigabatrin therapy.

Concepts: Nervous system, Retina, Photoreceptor cell, Visual system, Ophthalmology, Optic nerve, Visual field, Nerve fiber layer