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Transactions of the American... 1983The pathophysiologic events in optic nerve axons have recently been recognized as crucial to an understanding of clinically significant acquired alterations in the... (Review)
Review
The pathophysiologic events in optic nerve axons have recently been recognized as crucial to an understanding of clinically significant acquired alterations in the ophthalmoscopic appearance of the optic disc. Stasis and related abnormalities of axonal transport appear to explain most aspects of optic nerve head swelling, including optic disc drusen and retinal cottonwool spots. Loss of axoplasm and axonal death can be invoked to interpret optic disc pallor, thinning and narrowing of rim tissue, changes in the size and outline of the optic cup, laminar dots, atrophy of the retinal nerve fiber layer, and acquired demyelination and myelination of the retinal nerve fiber layer. It is speculated that the axons may also play a role in the mechanical support of the lamina cribrosa in resisting the pressure gradient across the pars scleralis of the optic nerve head. Axons and their associated glial cells may be involved in those cases where "reversibility" of cupping of the optic disc has been reported. The structure, physiology, and experimental pathologic findings of the optic nerve head have been reviewed. Many aspects concerning the final anatomic appearance of the optic nerve head have been explained. However, many questions remain concerning the intermediate mechanisms by which increased intracranial pressure retards the various components of axonal transport in papilledema and by which increased IOP causes axonal loss in glaucoma. Investigation of the molecular biology of axonal constituents and their responses to abnormalities in their physical and chemical milieu could extend our understanding of the events that result from mechanical compression and local ischemia. Moreover, we have identified a need to further explore the role of axons in the pathophysiology of optic disc cupping.
Topics: Animals; Autoradiography; Axonal Transport; Axons; Disease Models, Animal; Fluorescein Angiography; Humans; Intracranial Pressure; Macaca mulatta; Ocular Hypertension; Ophthalmoscopy; Optic Atrophy; Optic Disk; Optic Nerve; Optic Nerve Diseases
PubMed: 6203209
DOI: No ID Found -
Scientific Reports Feb 2017We investigated retinal structure and function in eyes with optic nerve hypoplasia (ONH). Twenty-nine eyes of 18 patients with ONH and 21 eyes of 21 control patients...
We investigated retinal structure and function in eyes with optic nerve hypoplasia (ONH). Twenty-nine eyes of 18 patients with ONH and 21 eyes of 21 control patients were analyzed. Spectral-domain optical coherence tomography (SD-OCT), full-field electroretinography (FF-ERG), and focal macular ERG (FM-ERG) were performed. SD-OCT analysis of the macular region showed significant ganglion cells complex (GCC) thinning nasally and temporally (P < 0.05), but the thickness from the inner nuclear layer (INL) to the retinal pigment epithelium (RPE) became thinner only nasally (P < 0.05). SD-OCT analysis of the circumpapillary region showed significant thinning in the retinal nerve fiber layer and from the INL to the RPE (P < 0.05). The horizontal SD-OCT images showed variable foveal abnormalities. FF-ERG analysis showed significantly reduced amplitudes (P < 0.05) and preserved implicit time in the photopic negative response. The amplitudes and implicit times of the other FF-ERG components did not differ significantly. FM-ERG analysis showed significantly reduced amplitudes (P < 0.05) but preserved implicit times in all components. The current study showed the change of retinal structure and function in eyes with ONH compared with those with control, representing by decreased retinal ganglion cells (RGCs) and their axons, foveal abnormalities, and preserved peripheral retina except for the RGCs and their axons.
Topics: Adolescent; Case-Control Studies; Child; Child, Preschool; Electroretinography; Female; Humans; Infant; Male; Optic Atrophy; Optic Disk; Optic Nerve; Retina; Tomography, Optical Coherence
PubMed: 28205530
DOI: 10.1038/srep42480 -
Anatomical Record (Hoboken, N.J. : 2007) Mar 2019The optic nerves (ONs), one of the 12 pairs of cranial nerves (Pair II), together with the olfactory and the cochlear nerves, are devoted to transmit sensory inputs. In... (Review)
Review
The optic nerves (ONs), one of the 12 pairs of cranial nerves (Pair II), together with the olfactory and the cochlear nerves, are devoted to transmit sensory inputs. In particular, ONs convey visual information from the retina to the brain. In mammals, the ONs are bilateral structures that extend from the optic disc to the optic chiasm containing glial cells and retinal ganglion cells (RGCs) axons. RGCs are the only retinal neurons able to collect visual information and transmit it to the visual centers in the brain for its processing and integration with the rest of sensory inputs. During embryonic development, RGCs born in the retina extend their axons to exit the eye and follow a stereotypic path outlined by the transient expression of a wide set of guidance molecules. As the rest of central nervous system structures, the ONs are covered with myelin produced by oligodendrocytes and wrapped by the meninges. ON injuries or RGCs degenerative conditions may provoke partial or complete blindness because they are incapable of spontaneous regeneration. Here, we first review major advances on the current knowledge about the mechanisms underlying the formation of the ONs in mammals. Then, we discuss some of the human disorders and pathologies affecting the development and function of the ONs and finally we comment on the existing view about ON regeneration possibilities. Anat Rec, 302:428-445, 2019. © 2018 Wiley Periodicals, Inc.
Topics: Animals; Axons; Cranial Nerves; Humans; Nerve Regeneration; Optic Nerve; Retinal Ganglion Cells
PubMed: 30306726
DOI: 10.1002/ar.23922 -
AJNR. American Journal of Neuroradiology Feb 2018Few articles in the literature have looked at the diameter of the optic nerve on MR imaging, especially in children, in whom observations are subjective and no normative...
BACKGROUND AND PURPOSE
Few articles in the literature have looked at the diameter of the optic nerve on MR imaging, especially in children, in whom observations are subjective and no normative data exist. The aim of this study was to establish a data base for optic nerve diameter measurements on MR imaging in the pediatric population.
MATERIALS AND METHODS
This was a retrospective study on the MR imaging of pediatric subjects (younger than 18 years of age) at the Department of Diagnostic Radiology at the American University of Beirut Medical Center, Beirut, Lebanon. The optic nerve measurements were obtained by 3 raters on axial and coronal sections at 3 mm (retrobulbar) and 7 mm (intraorbital) posterior to the lamina cribrosa.
RESULTS
Of 211 scans of patients (422 optic nerves), 377 optic nerves were measured and included. Ninety-four patients were female (45%) and the median age at MR imaging was 8.6 years (interquartile range, 3.9-13.3 years). Optic nerves were divided into 5 age groups: 0-6 months ( = 18), 6 months-2 years ( = 44), 2-6 years ( = 86), 6-12 years ( = 120), and 12-18 years ( = 109). An increase in optic nerve diameter was observed with age, especially in the first 2 years of life. Measurements did not differ with eye laterality or sex.
CONCLUSIONS
We report normative values of optic nerve diameter measured on MR imaging in children from birth to 18 years of age. A rapid increase in optic nerve diameter was demonstrated during the first 2 years of life, followed by a slower increase. This was independent of sex or eye laterality.
Topics: Adolescent; Child; Child, Preschool; Female; Humans; Infant; Magnetic Resonance Imaging; Male; Optic Nerve; Reference Values; Retrospective Studies
PubMed: 29217740
DOI: 10.3174/ajnr.A5456 -
Anesthesiology May 2008
Topics: Anemia; Anesthesiology; Animals; Humans; Hypotension; Intraocular Pressure; Optic Nerve; Postoperative Complications; Prone Position; Regional Blood Flow; Spine; Swine; Vision Disorders
PubMed: 18431112
DOI: 10.1097/ALN.0b013e31816d91e9 -
Journal of Neuroscience Methods Feb 2019Animal models of optic nerve injury are often used to study central nervous system (CNS) degeneration and regeneration, and targeting the optic nerve is a powerful...
BACKGROUND
Animal models of optic nerve injury are often used to study central nervous system (CNS) degeneration and regeneration, and targeting the optic nerve is a powerful approach for axon-protective or remyelination therapy. However, the experimental delivery of drugs or cells to the optic nerve is rarely performed because injections into this structure are difficult in small animals, especially in mice.
NEW METHOD
We investigated and developed methods to deliver drugs or cells to the mouse optic nerve through 3 different routes: a) intraorbital, b) through the optic foramen and c) transcranial.
RESULTS
The methods targeted different parts of the mouse optic nerve: intraorbital proximal (intraorbital), intracranial middle (optic-foramen) or intracranial distal (transcranial) portion.
COMPARISON WITH EXISTING METHODS
Most existing methods target the optic nerve indirectly. For instance, intravitreally delivered cells often cannot cross the inner limiting membrane to reach retinal neurons and optic nerve axons. Systemic delivery, eye drops and intraventricular injections do not always successfully target the optic nerve. Intraorbital and transcranial injections into the optic nerve or chiasm have been performed but these methods have not been well described. We approached the optic nerve with more selective and precise targeting than existing methods.
CONCLUSIONS
We successfully targeted the murine optic nerve intraorbitally, through the optic foramen, and transcranially. Of all methods, the injection through the optic foramen is likely the most innovative and fastest. These methods offer additional approaches for therapeutic intervention to be used by those studying white matter damage and axonal regeneration in the CNS.
Topics: Animals; Disease Models, Animal; Injections; Mice; Mice, Inbred C57BL; Optic Nerve; Orbit; Skull Base
PubMed: 30389488
DOI: 10.1016/j.jneumeth.2018.10.038 -
Current Biology : CB Jun 2022Consider how advantageous it might be to have eyes on our hands, rather than on our faces: depth perception would be improved by the greater distance between the eyes,...
Consider how advantageous it might be to have eyes on our hands, rather than on our faces: depth perception would be improved by the greater distance between the eyes, and it would be easy to look into relatively inaccessible spaces by appropriate movement of the hands. The absence of mammals that use this visual strategy draws attention to constraints on how evolution is able to 'design' the nervous system. Energy use in particular, in this case the large amount of energy that would be needed to send visual information along the ∼10 optic nerve axons over the length of the arms to the brain (instead of along the much shorter optic nerve), imposes significant design constraints on the nervous system.
Topics: Animals; Axons; Brain; Eye; Mammals; Neurons; Optic Nerve
PubMed: 35728547
DOI: 10.1016/j.cub.2022.02.005 -
BMC Anesthesiology Jan 2021The results of studies on changes in intracranial pressure in patients undergoing laparoscopic surgery are inconsistent. Meanwhile, previous neurosurgery studies have... (Randomized Controlled Trial)
Randomized Controlled Trial
Effects of sevoflurane and propofol on the optic nerve sheath diameter in patients undergoing laparoscopic gynecological surgery: a randomized controlled clinical studies.
BACKGROUND
The results of studies on changes in intracranial pressure in patients undergoing laparoscopic surgery are inconsistent. Meanwhile, previous neurosurgery studies have suggested that propofol and sevoflurane have inconsistent effects on cerebral blood flow and cerebrovascular self-regulation. The purpose of this study is to compare changes in the optic nerve sheath diameter in patients undergoing laparoscopic gynecological surgery under anesthetic maintenance with propofol versus sevoflurane.
METHODS
This study included 110 patients undergoing laparoscopic gynecological surgery with an estimated operative time of more than 2 h under general anesthesia. The study was a randomized controlled study. The optic nerve sheath diameter (ONSD) at various time points was measured by ultrasound, including when the patients entered the operating room (Tawake), after successful anesthesia induction and endotracheal intubation (Tinduction), when the body position was adjusted to the Trendelenburg position and the CO pneumoperitoneum pressure reached 14 mmHg, which was recorded as T. Then, measurements were conducted every 15 min for the first 1 h and then once every hour until the end of the surgery (T, T, T, T, T …), after the end of surgery and the tracheal tube was removed (T), and before the patients were transferred to the ward (T).
RESULTS
A significant difference in optic nerve sheath diameter was found between two groups at T, T, T (4.64 ± 0.48 mm and 4.50 ± 0.29 mm, respectively, p = 0.031;4.77 ± 0.45 mm and 4.62 ± 0.28 mm, respectively, p = 0.036;4.84 ± 0.46 mm and 4.65 ± 0.30 mm, respectively, p = 0.012), while there was no significant difference at T and other time points.
CONCLUSION
During laparoscopic gynecological surgery lasting more than 2 h, the optic nerve sheath diameter was slightly larger in the propofol group than that in the sevoflurane group in the first 45 min. No significant difference was observed between the two groups 1 h after surgery.
TRIAL REGISTRATION
clinicaltrials.gov, NCT03498235 . Retrospectively registered 1 March 2018. The manuscript adheres to CONSORT guidelines.
Topics: Adult; Anesthetics, Inhalation; Anesthetics, Intravenous; Female; Gynecologic Surgical Procedures; Humans; Laparoscopy; Optic Nerve; Propofol; Sevoflurane
PubMed: 33504329
DOI: 10.1186/s12871-021-01243-7 -
PloS One 2018This study was to evaluate whether optic nerve damage occurs in eyes with adjacent chronic sinusitis.
PURPOSE
This study was to evaluate whether optic nerve damage occurs in eyes with adjacent chronic sinusitis.
METHODS
Data were collected from eighty-eight eyes of 46 chronic sinusitis patients and 93 eyes of 57 normal controls. Visual sensitivity using standard automated perimetry (SAP) and inner retinal thickness using optical coherence tomography (OCT) were measured. The Lund-Mackay system was used to quantify radiographic findings on the ostiomeatal unit CT scan with a numerical score representing the severity of sinusitis.
RESULTS
There was a significant positive correlation between the pattern standard deviation (dB) and Lund-Mackay score (P = 0.031). Nasal retinal nerve fiber layer (RNFL) thickness, average, minimum, superotemporal, superior, superonasal, and inferonasal ganglion cell-inner plexiform layer (GCIPL) thickness were negatively correlated significantly with Lund-Mackay score (all, P < 0.05). Eyes with grade 2 opacification of the posterior ethmoid sinus showed a significantly lower mean deviation (dB) and higher pattern standard deviation (dB) than those with clear respective sinuses (P = 0.007 and <0.001, respectively). Eyes with grades 1,2 and 3 opacification of the sphenoid sinus had a significantly less average RNFL thickness (P = 0.004, <0.001, and <0.001, respectively) and a significantly less average GCIPL thickness (P = 0.004, 0.003, and 0.003, respectively) than those with a clear sphenoid sinus.
CONCLUSIONS
Structural and functional optic nerve changes were correlated with the severity of chronic sinusitis. Inflammation of the posterior ethmoid and sphenoid sinuses was associated with optic nerve changes to a greater extent than that of the other paranasal sinuses.
Topics: Adult; Aged; Female; Humans; Male; Middle Aged; Optic Nerve; Optic Nerve Diseases; Sinusitis
PubMed: 29990384
DOI: 10.1371/journal.pone.0199875 -
The British Journal of Ophthalmology May 1998Three separate experimental models of optic nerve regeneration have been presented--along the existing pathway in the presence of antibodies to neutralise inhibitory... (Review)
Review
Three separate experimental models of optic nerve regeneration have been presented--along the existing pathway in the presence of antibodies to neutralise inhibitory molecules, along peripheral nerve grafts and from retinal transplants. Each offers a theoretical clinical strategy for restoration of vision, if the mechanism of re-establishment of maps and reconnection to appropriate targets during regeneration can be determined. This is the process of axon guidance, and underlines the importance of our research into the molecular determinants that guide normal development of the visual system.
Topics: Animals; Astrocytes; Axons; Central Nervous System; Humans; Nerve Regeneration; Oligodendroglia; Optic Nerve; Optic Nerve Injuries; Peripheral Nerves
PubMed: 9713068
DOI: 10.1136/bjo.82.5.577