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Archives of Ophthalmology (Chicago,... Nov 1992Optic nerve aplasia is a rare congenital defect invariably associated with other ocular or systemic disorders. We examined a 3-year-old girl with monocular...
Optic nerve aplasia is a rare congenital defect invariably associated with other ocular or systemic disorders. We examined a 3-year-old girl with monocular microphthalmos who had optic nerve aplasia on histopathologic examination of the eye after enucleation. Magnetic resonance imaging verified the presence of unilateral optic nerve aplasia, and demonstrated hemichiasmal hypoplasia on the affected side and bilateral optic tracts. The visually evoked cortical response revealed increased signals over the occipital cortex ipsilateral to the aplastic nerve, suggesting misdirection of axons from the temporal retina of the normal eye. The visual pathway in unilateral optic nerve aplasia may assume a primitive form of neuronal organization characterized by an increase in contralateral retinogeniculostriate projection.
Topics: Child, Preschool; Dark Adaptation; Evoked Potentials, Visual; Eye Enucleation; Female; Humans; Magnetic Resonance Imaging; Microphthalmos; Optic Nerve
PubMed: 1444922
DOI: 10.1001/archopht.1992.01080230110033 -
The British Journal of Ophthalmology May 1990Optic nerve hypoplasia (ONH) is characterised by a diminished number of optic nerve fibres in the optic nerve(s) and until recently was thought to be rare. It may be... (Review)
Review
Optic nerve hypoplasia (ONH) is characterised by a diminished number of optic nerve fibres in the optic nerve(s) and until recently was thought to be rare. It may be associated with a wide range of other congenital abnormalities. Its pathology, clinical features, and the conditions associated with it are reviewed. Neuroendocrine disorders should be actively sought in any infant or child with bilateral ONH. Early recognition of the disorder may in some cases be life saving.
Topics: Abnormalities, Multiple; Humans; Infant; Optic Nerve; Vision Disorders
PubMed: 2191713
DOI: 10.1136/bjo.74.5.300 -
Journal of Pediatric Ophthalmology and... 2023
Topics: Humans; Infant; Retinal Detachment; Optic Nerve; Optic Disk
PubMed: 37478201
DOI: 10.3928/01913913-20230503-01 -
Vestnik Oftalmologii 2024Optic nerve atrophy is a pathomorphological consequence of diseases of the peripheral neuron of the visual pathway, manifested as atrophy of nerve fibers of varying... (Review)
Review
Optic nerve atrophy is a pathomorphological consequence of diseases of the peripheral neuron of the visual pathway, manifested as atrophy of nerve fibers of varying severity. The toxic effect of methanol is mainly associated with formic acid and formaldehyde, which suppress the cytochrome system, inhibit oxidative phosphorylation, and thereby cause a deficiency of adenosine triphosphoric acid, to which brain and retinal tissues are especially susceptible. When formiate accumulates, tissue respiration is disrupted, leading to pronounced tissue hypoxia. As a result of such methanol metabolism, metabolic acidosis occurs. Tissue hypoxia develops in the first few hours as a result of the action of formic acid on the respiratory enzyme chain at the cytochrome oxidase level. Hypoxia and, as a consequence, a decrease in energy supply lead to a disruption of biological oxidation and the development of apoptosis in the optic nerve fibers. Understanding the process of optic nerve atrophy development at the pathogenetic level in methyl alcohol intoxication will help make a correct early diagnosis and prescribe timely treatment.
Topics: Humans; Methanol; Optic Nerve; Optic Atrophy
PubMed: 38742504
DOI: 10.17116/oftalma202414002191 -
PloS One 2020Several studies have shown an association between intracranial pressure and the diameter of the optic nerve sheath measured by transbulbar ultrasonography. To understand...
OBJECTIVE
Several studies have shown an association between intracranial pressure and the diameter of the optic nerve sheath measured by transbulbar ultrasonography. To understand the pathophysiology of this phenomenon, we aimed to measure the changes of the optic nerve, optic nerve sheath and perineural space separately with increasing intracranial pressure in a porcine model.
METHODS
An external ventricular drain was placed into the third ventricle through a right paramedian burrhole in eight anesthesized pigs. The diameters of the optic nerve and the optic nerve sheath were measured while the intracranial pressure (ICP) was increased in steps of 10mmHg from baseline up to 60 mmHg.
RESULTS
The median diameters of the optic nerve (ON) increased from 0.36 cm (baseline- 95% confidence interval (CI) 0.33 cm to 0.45 cm) to 0.68 cm (95% CI 0.57 cm to 0.82 cm) at ICP of 60 mmHg (p<0.0001) and optic nerve sheath (ONS) from 0.88 cm (95% CI 0.79 cm to 0.98 cm) to 1.24 cm (95% CI 1.02 cm to 1.38 cm) (p< 0.002) while the median diameter of the perineural space (PNS) (baseline diameter 95% CI 0.40 cm to 0.59 cm to diameters at ICP 60 95% CI 0.38 cm to 0.62 cm) did not change significantly (p = 0.399). Multiple comparisons allowed differentiation between baseline and values ≥40 mmHg for ON (p = 0.017) and between baseline and values ≥ 50mmHg for ONS (p = 0.006). A linear correlation between ON (R2 = 0.513, p<0.0001) and ONS (R2 = 0.364, p<0.0001) with ICP was found. The median coefficient of variation for intra- and inter-investigator variability was 8% respectively 2.3%.
CONCLUSION
Unexpectedly, the increase in ONS diameter with increasing ICP is exclusively related to the increase of the diameter of the ON. Further studies should explore the reasons for this behaviour.
Topics: Animals; Hemodynamics; Intracranial Pressure; Optic Nerve; Swine; Ultrasonography
PubMed: 32017786
DOI: 10.1371/journal.pone.0228242 -
International Journal of Developmental... Feb 2014Developmental abnormalities of optic nerve are the leading cause of child blindness. The goal of this study was to use diffusion tensor imaging (DTI) to characterize the... (Review)
Review
Developmental abnormalities of optic nerve are the leading cause of child blindness. The goal of this study was to use diffusion tensor imaging (DTI) to characterize the optic nerve development of non-human primates during the normal maturation from birth to adulthood. Forty healthy rhesus monkeys aged from 2 weeks to 6 years old were scanned with a clinical 3T scanner. It was demonstrated that the DTI parameters followed an exponential pattern during optic nerve maturation. The time constants of mean diffusivity (MD), fractional anisotropy (FA), axial diffusivity (λ∥) and radial diffusivity (λ⊥) were 16, 14, 18 and 15 months in rhesus monkeys, respectively. Significant decrease in RD was observed firstly at 12 months after birth (p<0.05). No significant differences were observed between the left and right optic nerves in any age group. The in vivo imaging results reveal the normal evolution patterns of DTI parameters during optic nerve maturation in primates. The data might be used as a reference in the examination of optic nerve developmental abnormalities or injury in children or preclinical studies.
Topics: Analysis of Variance; Animals; Animals, Newborn; Anisotropy; Decision Making, Computer-Assisted; Diffusion Tensor Imaging; Macaca mulatta; Optic Nerve
PubMed: 23831120
DOI: 10.1016/j.ijdevneu.2013.06.007 -
Acta Anaesthesiologica Scandinavica Jul 2011The rapid diagnosis of intracranial hypertension is urgently needed for therapeutic reasons in various clinical settings. This can rarely be achieved without invasive... (Review)
Review
The rapid diagnosis of intracranial hypertension is urgently needed for therapeutic reasons in various clinical settings. This can rarely be achieved without invasive procedures such as intracranial pressure (ICP) monitoring or neuroimaging. The optic nerve is surrounded by cerebrospinal fluid (CSF) and dura mater, which forms the optic nerve sheath (ONS). Because of the connection with the intracranial subarachnoid space, ONS diameter (ONSD) is influenced by CSF pressure variations. Bedside ultrasonographic measurement of ONSD has been proposed as a non-invasive and reliable means to detect raised ICP in neurocritically ill patients. In several studies, it proves to have a good correlation with the direct measurement of ICP and a low interobserver variability. However, no general consensus exists over the upper normal ONSD limit. We performed a review of the literature on the use of the ultrasonography of the optic nerve in the evaluation of patients with suspected intracranial hypertension. The aim of this review is to describe the technique and to assess the validity of this diagnostic method.
Topics: Cerebrospinal Fluid Pressure; Critical Illness; Humans; Intracranial Hypertension; Intracranial Pressure; Optic Nerve; Ultrasonography, Doppler, Transcranial
PubMed: 21463263
DOI: 10.1111/j.1399-6576.2011.02432.x -
PloS One 2022Diffusion-weighted magnetic resonance imaging of the human optic nerve and tract is technically difficult because of its small size, the inherent strong signal generated...
Diffusion-weighted magnetic resonance imaging of the human optic nerve and tract is technically difficult because of its small size, the inherent strong signal generated by the surrounding fat and the cerebrospinal fluid, and due to eddy current-induced distortions and subject movement artifacts. The effects of the bone canal through which the optic nerve passes, and the proximity of blood vessels, muscles and tendons are generally unknown. Also, the limited technical capabilities of the scanners and the minimization of acquisition times result in poor quality diffusion-weighted images. It is challenging for current tractography methods to accurately track optic pathway fibers that correspond to known anatomy. Despite these technical limitations and low image resolution, here we show how to visualize the optic nerve and tract and quantify nerve atrophy. Our visualization method based on the analysis of the diffusion tensor shows marked differences between a healthy male subject and a male subject with progressive optic nerve neuropathy. These differences coincide with diffusion scalar metrics and are not visible on standard morphological images. A quantification of the degree of optic nerve atrophy in a systematic way is provided and it is tested on 9 subjects from the Human Connectome Project.
Topics: Humans; Male; Diffusion Tensor Imaging; Optic Nerve; Diffusion Magnetic Resonance Imaging; Connectome; Peripheral Nervous System Diseases; Atrophy
PubMed: 36508429
DOI: 10.1371/journal.pone.0278987 -
Development, Growth & Differentiation Sep 2010The pathway from the retina to the brain in mammals provides a well-defined model system for investigation of not only surviving axotomy but also axonal regeneration of... (Review)
Review
The pathway from the retina to the brain in mammals provides a well-defined model system for investigation of not only surviving axotomy but also axonal regeneration of injured neurons. Here I introduce our recent works on axonal regeneration in the optic nerve (OpN) of adult cats. Fibers of retinal ganglion cells (RGCs) extend beyond the crush site of OpN with injections of a macrophage stimulator (oxidized galectin-1) or a Rho kinase (ROCK) inhibitor (Y-39983 or Y-27632) while axonal extension is blocked with injection of saline. Elongation of crushed optic fibers, however, is slowed after 2 weeks. Transplantation of peripheral nerve makes RGCs regenerate their transected axons into a graft but regenerated fibers extend only a few mm in the brain. Effectiveness of combination of the drugs and treatments has to be verified in future.
Topics: Adrenergic Antagonists; Animals; Cell Differentiation; Humans; Mammals; Nerve Fibers; Nerve Regeneration; Optic Nerve
PubMed: 20887558
DOI: 10.1111/j.1440-169X.2010.01203.x -
Acta Radiologica (Stockholm, Sweden :... Jan 2022Changes in optic nerve vascularity are observed in many diseases. Superb microvascular imaging (SMI) has the potential to become the method of choice for detecting...
BACKGROUND
Changes in optic nerve vascularity are observed in many diseases. Superb microvascular imaging (SMI) has the potential to become the method of choice for detecting microvasculature in the optic nerves.
PURPOSE
To evaluate optic nerve vascularity in healthy individuals through power Doppler sonography (PDUS) and SMI.
MATERIAL AND METHODS
Twenty-seven healthy patients with 54 eyes were prospectively evaluated. The duration of the examination for optic nerve vascularity lasted until the posterior ciliary artery blood supply was observed in PDUS and SMI. The visibility of vascularity, as well as the ratio of the vascular structures to the optic nerves (vascular index [VI]), was evaluated.
RESULTS
Fifty-four eyes were evaluated from a total of 27 patients (mean age = 49.0 ± 19.42 years). The VI value for the right optic nerve was 29.58 ± 4.00 while for the left optic nerve, it was 31.21 ± 3.52. Vascularity was clearly observed in both eyes (n = 54) in all 27 cases in the evaluation performed with the SMI technique. However, with the power Doppler examination, vascular flow was not observed in 14 right eyes and in 10 left eyes within the specified timeframe.
CONCLUSION
The results indicate that imaging of vascular structures can be done faster and better with SMI than PDUS examination. The normal VI values may provide important information about the blood supply of the optic nerve, which is of relevance in orbital pathologies and many systemic conditions.
Topics: Adult; Female; Humans; Male; Microvessels; Middle Aged; Optic Nerve; Prospective Studies; Ultrasonography, Doppler
PubMed: 33475431
DOI: 10.1177/0284185120983279