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Current Opinion in Neurology Feb 2017Acute optic neuritis is a common clinical problem, requiring a structured assessment to guide management and prevent visual loss. The optic nerve is the most accessible... (Review)
Review
PURPOSE OF REVIEW
Acute optic neuritis is a common clinical problem, requiring a structured assessment to guide management and prevent visual loss. The optic nerve is the most accessible part of the central nervous system, so optic neuritis also represents an important paradigm to help decipher mechanisms of damage and recovery in the central nervous system. Important developments include the advent of optical coherence tomography as a biomarker of central nervous system axonal loss, the discovery of new pathological antibodies, notably against aquaporin-4 and, more recently, myelin oligodendrocyte protein, and emerging evidence for sodium channel blockade as a novel therapeutic approach to address energy failure in neuroinflammatory disease.
RECENT FINDINGS
We will present a practical approach to assessment of optic neuritis, highlighting the role of optical coherence tomography, when to test for new antibodies and the results of recent trials of sodium channel blockers.
SUMMARY
Optic neuritis remains a clinical diagnosis; increasingly optical coherence tomography is a key ancillary investigation. Patients with 'typical' optic neuritis, commonly a first presentation of multiple sclerosis, must be distinguished from 'atypical' optic neuritis, who require testing for new pathological antibodies and require more aggressive-targeted treatment. Sodium channel blockade is an emerging and novel potential therapeutic pathway in neuroinflammatory disease.
Topics: Axons; Brain; Humans; Optic Nerve; Optic Neuritis; Tomography, Optical Coherence
PubMed: 27906756
DOI: 10.1097/WCO.0000000000000414 -
Investigative Ophthalmology & Visual... Aug 2017The eye and its accessory structures, the optic nerve and the extraocular muscles, form a complex dynamic system. In vivo magnetic resonance imaging (MRI) of this system...
PURPOSE
The eye and its accessory structures, the optic nerve and the extraocular muscles, form a complex dynamic system. In vivo magnetic resonance imaging (MRI) of this system in motion can have substantial benefits in understanding oculomotor functioning in health and disease, but has been restricted to date to imaging of static gazes only. The purpose of this work was to develop a technique to image the eye and its accessory visual structures in motion.
METHODS
Dynamic imaging of the eye was developed on a 3-Tesla MRI scanner, based on a golden angle radial sequence that allows freely selectable frame-rate and temporal-span image reconstructions from the same acquired data set. Retrospective image reconstructions at a chosen frame rate of 57 ms per image yielded high-quality in vivo movies of various eye motion tasks performed in the scanner. Motion analysis was performed for a left-right version task where motion paths, lengths, and strains/globe angle of the medial and lateral extraocular muscles and the optic nerves were estimated.
RESULTS
Offline image reconstructions resulted in dynamic images of bilateral visual structures of healthy adults in only ∼15-s imaging time. Qualitative and quantitative analyses of the motion enabled estimation of trajectories, lengths, and strains on the optic nerves and extraocular muscles at very high frame rates of ∼18 frames/s.
CONCLUSIONS
This work presents an MRI technique that enables high-frame-rate dynamic imaging of the eyes and orbital structures. The presented sequence has the potential to be used in furthering the understanding of oculomotor mechanics in vivo, both in health and disease.
Topics: Adult; Eye; Eye Movements; Female; Healthy Volunteers; Humans; Image Processing, Computer-Assisted; Magnetic Resonance Imaging; Male; Ocular Physiological Phenomena; Oculomotor Muscles; Optic Nerve; Retrospective Studies
PubMed: 28813574
DOI: 10.1167/iovs.17-21861 -
Biomechanics and Modeling in... Aug 2021The optic nerve (ON) is a recently recognized tractional load on the eye during larger horizontal eye rotations. In order to understand the mechanical behavior of the...
The optic nerve (ON) is a recently recognized tractional load on the eye during larger horizontal eye rotations. In order to understand the mechanical behavior of the eye during adduction, it is necessary to characterize material properties of the sclera, ON, and in particular its sheath. We performed tensile loading of specimens taken from fresh postmortem human eyes to characterize the range of variation in their biomechanical properties and determine the effect of preconditioning. We fitted reduced polynomial hyperelastic models to represent the nonlinear tensile behavior of the anterior, equatorial, posterior, and peripapillary sclera, as well as the ON and its sheath. For comparison, we analyzed tangent moduli in low and high strain regions to represent stiffness. Scleral stiffness generally decreased from anterior to posterior ocular regions. The ON had the lowest tangent modulus, but was surrounded by a much stiffer sheath. The low-strain hyperelastic behaviors of adjacent anatomical regions of the ON, ON sheath, and posterior sclera were similar as appropriate to avoid discontinuities at their boundaries. Regional stiffnesses within individual eyes were moderately correlated, implying that mechanical properties in one region of an eye do not reliably reflect properties of another region of that eye, and that potentially pathological combinations could occur in an eye if regional properties are discrepant. Preconditioning modestly stiffened ocular tissues, except peripapillary sclera that softened. The nonlinear mechanical behavior of posterior ocular tissues permits their stresses to match closely at low strains, although progressively increasing strain causes particularly great stress in the peripapillary region.
Topics: Adult; Aged; Aged, 80 and over; Biomechanical Phenomena; Elasticity; Eye; Female; Finite Element Analysis; Head; Humans; Male; Middle Aged; Optic Disk; Optic Nerve; Sclera; Stress, Mechanical; Tensile Strength
PubMed: 33877503
DOI: 10.1007/s10237-021-01448-2 -
Scientific Reports Dec 2017The association between corneal biomechanical properties and glaucoma is an area of much interest. We determined the relationship between corneal hysteresis (CH) and...
The association between corneal biomechanical properties and glaucoma is an area of much interest. We determined the relationship between corneal hysteresis (CH) and optic nerve parameters in healthy myopic subjects in the current study. CH was measured with Reichert Ocular Response Analyzer in 108 eyes from 108 healthy myopic subjects. All subjects received retinal nerve fiber layer and optic disc imaging Cirrus HD-OCT, GDx ECC, and Heidelberg Retina Tomograph II. None of the tested optic nerve parameters showed statistical significance with CH by using correlation analysis. For RNFL parameters, there was a negative but not statistically significant correlation between CH and average RNFL thickness obtained with OCT (r = -0.15, p = 0.13). For optic disc parameters, there was a negative but not statistically significant correlation between CH and rim area measured with OCT (r = -0.10, p = 0.29). The current study did not find any statistically significant relationship between CH and optic nerve parameters as measured by all three imaging modalities in healthy myopic eyes. Therefore, the relationship observed previously in glaucoma subjects is likely coming to fruition as optic nerve damage is caused by the disease.
Topics: Adolescent; Adult; Biomechanical Phenomena; Cornea; Female; Humans; Male; Myopia; Optic Nerve; Organ Size; Young Adult
PubMed: 29235544
DOI: 10.1038/s41598-017-15386-6 -
Molecular & Cellular Proteomics : MCP Nov 2023The pathogenesis of glaucoma is still unknown. There are few studies on the dynamic change of tissue-specific and time-specific molecular pathophysiology caused by...
The pathogenesis of glaucoma is still unknown. There are few studies on the dynamic change of tissue-specific and time-specific molecular pathophysiology caused by ocular hypertension (OHT). This study aimed to identify the early proteomic alterations in the retina, optic nerve head (ONH), and optic nerve (ON). After establishing a rat model of OHT, we harvested the tissues from control and glaucomatous eyes and analyzed the changes in protein expression using a multiplexed quantitative proteomics approach (TMT-MS3). Our study identified 6403 proteins after 1-day OHT and 4399 proteins after 7-days OHT in the retina, 5493 proteins after 1-day OHT and 4544 proteins after 7-days OHT in ONH, and 5455 proteins after 1-day OHT and 3835 proteins after 7-days OHT in the ON. Of these, 560 and 489 differential proteins were identified on day 1 and 7 after OHT in the retina, 428 and 761 differential proteins were identified on day 1 and 7 after OHT in the ONH, and 257 and 205 differential proteins on days 1 and 7 after OHT in the ON. Computational analysis on day 1 and 7 of OHT revealed that alpha-2 macroglobulin was upregulated across two time points and three tissues stably. The differentially expressed proteins between day 1 and 7 after OHT in the retina, ONH, and ON were associated with glutathione metabolism, mitochondrial dysfunction/oxidative phosphorylation, oxidative stress, microtubule, and crystallin. And the most significant change in retina are crystallins. We validated this proteomic result with the Western blot of crystallin proteins and found that upregulated on day 1 but recovered on day 7 after OHT, which are promising as therapeutic targets. These findings provide insights into the time- and region-order mechanisms that are specifically affected in the retina, ONH, and ON in response to elevated IOP during the early stages.
Topics: Rats; Animals; Optic Disk; Proteomics; Intraocular Pressure; Glaucoma; Retina; Ocular Hypertension; Optic Nerve; Crystallins
PubMed: 37793503
DOI: 10.1016/j.mcpro.2023.100654 -
Journal of Medical Virology Jan 2021
Topics: COVID-19; Humans; Optic Nerve; SARS-CoV-2
PubMed: 32648939
DOI: 10.1002/jmv.26290 -
NeuroImage Aug 2019In vivo human optic nerve diffusion magnetic resonance imaging (dMRI) is technically challenging with two outstanding issues not yet well addressed: (i) non-linear optic...
In vivo human optic nerve diffusion magnetic resonance imaging (dMRI) is technically challenging with two outstanding issues not yet well addressed: (i) non-linear optic nerve movement, independent of head motion, and (ii) effect from partial-volumed cerebrospinal fluid or interstitial fluid such as in edema. In this work, we developed a non-linear optic nerve registration algorithm for improved volume alignment in axial high resolution optic nerve dMRI. During eyes-closed dMRI data acquisition, optic nerve dMRI measurements by diffusion tensor imaging (DTI) with and without free water elimination (FWE), and by diffusion basis spectrum imaging (DBSI), as well as optic nerve motion, were characterized in healthy adults at various locations along the posterior-to-anterior dimension. Optic nerve DTI results showed consistent trends in microstructural parametric measurements along the posterior-to-anterior direction of the entire intraorbital optic nerve, while the anterior portion of the intraorbital optic nerve exhibited the largest spatial displacement. Multi-compartmental dMRI modeling, such as DTI with FWE or DBSI, was less subject to spatially dependent biases in diffusivity and anisotropy measurements in the optic nerve which corresponded to similar spatial distributions of the estimated fraction of isotropic diffusion components. DBSI results derived from our clinically feasible (∼10 min) optic nerve dMRI protocol in this study are consistent with those from small animal studies, which provides the basis for evaluating the utility of multi-compartmental dMRI modeling in characterizing coexisting pathophysiology in human optic neuropathies.
Topics: Adult; Algorithms; Diffusion Tensor Imaging; Female; Humans; Image Processing, Computer-Assisted; Male; Optic Nerve; Signal Processing, Computer-Assisted; Signal-To-Noise Ratio; Young Adult
PubMed: 30930313
DOI: 10.1016/j.neuroimage.2019.03.058 -
Aging Cell Jan 2022As the mammalian central nervous system matures, its regenerative ability decreases, leading to incomplete or non-recovery from the neurodegenerative diseases and...
As the mammalian central nervous system matures, its regenerative ability decreases, leading to incomplete or non-recovery from the neurodegenerative diseases and central nervous system insults that we are increasingly facing in our aging world population. Current neuroregenerative research is largely directed toward identifying the molecular and cellular players that underlie central nervous system repair, yet it repeatedly ignores the aging context in which many of these diseases appear. Using an optic nerve crush model in a novel biogerontology model, that is, the short-living African turquoise killifish, the impact of aging on injury-induced optic nerve repair was investigated. This work reveals an age-related decline in axonal regeneration in female killifish, with different phases of the repair process being affected depending on the age. Interestingly, as in mammals, both a reduced intrinsic growth potential and a non-supportive cellular environment seem to lie at the basis of this impairment. Overall, we introduce the killifish visual system and its age-dependent regenerative ability as a model to identify new targets for neurorepair in non-regenerating individuals, thereby also considering the effects of aging on neurorepair.
Topics: Age Factors; Animals; Fundulidae; Nerve Regeneration; Optic Nerve
PubMed: 34927348
DOI: 10.1111/acel.13537 -
Documenta Ophthalmologica. Advances in... Apr 2021To describe the trans-occipital asymmetries of pattern and flash visual evoked potentials (VEPs), in an infant with MRI findings of unilateral optic nerve aplasia and...
PURPOSE
To describe the trans-occipital asymmetries of pattern and flash visual evoked potentials (VEPs), in an infant with MRI findings of unilateral optic nerve aplasia and hemi-chiasm dysplasia.
METHODS
A child with suspected left cystic microphthalmia, left microcornea, left unilateral optic nerve aplasia, and hemi-chiasm underwent a multi-channel VEP assessment with pattern reversal, pattern onset, and flash stimulation at the age of 16 weeks.
RESULTS
There was no VEP evidence of any post-retinal visual pathway activation from left eye with optic nerve aplasia. The VEP trans-occipital distribution from the functional right eye was skewed markedly across the midline, in keeping with significant misrouting of optic nerve fibres at the chiasm. This was supported by the anatomical trajectory of the optic chiasm and tracts seen on MRI.
CONCLUSION
This infant has chiasmal misrouting in association with unilateral optic nerve aplasia and unilateral microphthalmos. Chiasmal misrouting has not been found in patients with microphthalmos or anophthalmos, but has been reported after early eye loss in animal models. Our findings contribute to our understanding of the discrepancy between the visual pathway physiology of human unilateral microphthalmia and animal models.
Topics: Electroretinography; Evoked Potentials, Visual; Humans; Infant; Optic Chiasm; Optic Nerve; Optic Nerve Diseases
PubMed: 32852652
DOI: 10.1007/s10633-020-09788-7 -
Scientific Reports Mar 2020Computer vision has greatly advanced recently. Since AlexNet was first introduced, many modified deep learning architectures have been developed and they are still...
Computer vision has greatly advanced recently. Since AlexNet was first introduced, many modified deep learning architectures have been developed and they are still evolving. However, there are few studies comparing these architectures in the field of ophthalmology. This study compared the performance of various state-of-the-art deep-learning architectures for detecting the optic nerve head and vertical cup-to-disc ratio in fundus images. Three different architectures were compared: YOLO V3, ResNet, and DenseNet. We compared various aspects of performance, which were not confined to the accuracy of detection but included, as well, the processing time, diagnostic performance, effect of the graphic processing unit (GPU), and image resolution. In general, as the input image resolution increased, the classification accuracy, localization error, and diagnostic performance all improved, but the optimal architecture differed depending on the resolution. The processing time was significantly accelerated with GPU assistance; even at the high resolution of 832 × 832, it was approximately 170 ms, which was at least 26 times slower without GPU. The choice of architecture may depend on the researcher's purpose when balancing between speed and accuracy. This study provides a guideline to determine deep learning architecture, optimal image resolution, and the appropriate hardware.
Topics: Aged; Algorithms; Deep Learning; Diagnostic Techniques, Ophthalmological; Female; Fundus Oculi; Glaucoma; Humans; Male; Middle Aged; Optic Nerve; Retrospective Studies
PubMed: 32193499
DOI: 10.1038/s41598-020-62022-x