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Glia May 2023Optic nerve head (ONH) astrocytes provide structural and metabolic support to neuronal axons in developmental, physiological, and pathological progression....
Optic nerve head (ONH) astrocytes provide structural and metabolic support to neuronal axons in developmental, physiological, and pathological progression. Mechanosensitive properties of astrocytes allow them to sense and respond to mechanical cues from the local environment. We confirmed that ONH astrocytes express the mechanosensitive ion channel Piezo1 in vivo. By manipulating Piezo1 knockdown or overexpression in vitro, we found that Piezo1 is necessary but insufficient for ONH astrocyte proliferation. Loss of Piezo1 can lead to cell cycle arrest at G0/G1 phase, a possible mechanism involving decreased yes-associated protein (YAP) nuclear localization and downregulation of YAP-target cell cycle-associated factors, including cyclin D1 and c-Myc. Gene ontology enrichment analysis of differential expression genes from RNA-seq data indicates that the absence of Piezo1 affects biological processes involving cell division. Our results demonstrate that Piezo1 is an essential regulator in cell cycle progression in ONH astrocytes.
Topics: Optic Disk; Astrocytes; Cell Division; Ion Channels; Cell Cycle
PubMed: 36598105
DOI: 10.1002/glia.24334 -
Eye (London, England) Jan 2021Optical coherence tomography (OCT) is a non-invasive medical imaging technology that is playing an increasing role in the routine assessment and management of patients... (Review)
Review
Optical coherence tomography (OCT) is a non-invasive medical imaging technology that is playing an increasing role in the routine assessment and management of patients with neuro-ophthalmic conditions. Its ability to characterise the optic nerve head, peripapillary retinal nerve fibre layer and cellular layers of the macula including the ganglion cell layer enables qualitative and quantitative assessment of optic nerve disease. In this review, we discuss technical features of OCT and OCT-based imaging techniques in the neuro-ophthalmic context, potential pitfalls to be aware of, and specific applications in more common neuro-ophthalmic conditions including demyelinating, inflammatory, ischaemic and compressive optic neuropathies, optic disc drusen and raised intracranial pressure. We also review emerging applications of OCT angiography within neuro-ophthalmology.
Topics: Humans; Ophthalmology; Optic Disk; Optic Disk Drusen; Optic Nerve Diseases; Tomography, Optical Coherence
PubMed: 33239763
DOI: 10.1038/s41433-020-01288-x -
Survey of Ophthalmology 2019Optic disk pit, one of the optic disk cavitary anomalies, is generally congenital and unilateral and occurs equally in males and females. Optic disk pit maculopathy is... (Review)
Review
Optic disk pit, one of the optic disk cavitary anomalies, is generally congenital and unilateral and occurs equally in males and females. Optic disk pit maculopathy is characterized by intraretinal and subretinal fluid at the macula, causing visual deterioration. The origin of the macular fluid and the mechanism of transition to the subretinal space in optic disk pit maculopathy pathophysiology are not yet fully understood. With the evolution of imaging modalities, especially optic coherence tomography, our knowledge of this disorder continues to increase. Although many different treatments have been tried, there is no consensus on the most effective.
Topics: Eye Diseases, Hereditary; Humans; Macula Lutea; Macular Degeneration; Optic Disk; Tomography, Optical Coherence; Visual Acuity
PubMed: 30797884
DOI: 10.1016/j.survophthal.2019.02.006 -
International Ophthalmology Clinics 2019
Review
Topics: Humans; Intracranial Hypertension; Intracranial Pressure; Optic Disk; Papilledema
PubMed: 31233413
DOI: 10.1097/IIO.0000000000000274 -
Survey of Ophthalmology 2024Intraretinal or subretinal fluid in the peripapillary area can be clinically visualized in conditions such as peripapillary choroidal neovascularization, optic disc pit... (Review)
Review
Intraretinal or subretinal fluid in the peripapillary area can be clinically visualized in conditions such as peripapillary choroidal neovascularization, optic disc pit maculopathy, and optic nerve head tumors and granulomas. Optical coherence tomography (OCT) helps to visualize peripapillary fluid in many other chorioretinal conditions such as peripapillary pachychoroid syndrome, posterior uveitis, central retinal vein occlusion, malignant hypertension, hypotonic maculopathy as well as neuro-ophthalmological conditions such as glaucoma, microcystic macular edema and disc edema due papilledema, non-arteritic anterior ischemic optic neuropathy, neuroretinitis, and diabetic papillopathy. Often, the differential diagnosis of peripapillary fluid is a bit tricky and may lead to misdiagnosis and improper management. We describe a diagnostic algorithm for peripapillary fluid on OCT and outline the salient features and management of these conditions.
Topics: Humans; Tomography, Optical Coherence; Optic Disk; Subretinal Fluid; Diagnosis, Differential; Retinal Diseases
PubMed: 38016521
DOI: 10.1016/j.survophthal.2023.11.004 -
Indian Journal of Ophthalmology Dec 2019Melanocytoma is a deeply pigmented variant of melanocytic nevus that classically occurs in the optic disk, sometimes with contiguous involvement of the adjacent retina... (Review)
Review
Melanocytoma is a deeply pigmented variant of melanocytic nevus that classically occurs in the optic disk, sometimes with contiguous involvement of the adjacent retina or choroid. Historically, this tumor was often confused with malignant melanoma both clinically and histopathologically. Today, however, it is generally recognized by its typical clinical features that differ from most melanomas and erroneous enucleation is rarely done. Histopathologically, melanocytoma is composed of intensely pigmented round to oval nevus cells with benign features. Although traditionally believed to be a relatively stationary lesion, it is now known to exhibit minor enlargement in 10--15% of cases and can cause minor visual loss by a variety of mechanisms. In rare instance, it can induce severe visual loss due to spontaneous necrosis of the lesion or compressive optic neuropathy. More importantly, it can exhibit malignant transformation into melanoma in 1--2% of cases. Ophthalmologists should be familiar with melanocytoma of the optic disk and affected patients should be followed periodically.
Topics: Cell Transformation, Neoplastic; Humans; Melanoma; Nevus, Pigmented; Optic Disk; Optic Nerve Neoplasms
PubMed: 31755427
DOI: 10.4103/ijo.IJO_2039_19 -
Ophthalmology Feb 2021The spaceflight-associated neuro-ocular syndrome (SANS) affects astronauts on missions to the International Space Station (ISS). The SANS has blurred vision and ocular...
PURPOSE
The spaceflight-associated neuro-ocular syndrome (SANS) affects astronauts on missions to the International Space Station (ISS). The SANS has blurred vision and ocular changes as typical features. The objective of this study was to investigate if microgravity can create deformations or movements of the eye or optic nerve, and if such changes could be linked to SANS.
DESIGN
Cohort study.
PARTICIPANTS
Twenty-two astronauts (age 48 ± 4 years).
METHODS
The intervention consisted of time in microgravity at the ISS. We co-registered pre- and postspaceflight magnetic resonance imaging (MRI) scans and generated centerline representations of the optic nerve. The coordinates for the optic nerve head (ONH) and optic chiasm (OC) ends of the optic nerve were recorded along with the entire centerline path.
MAIN OUTCOME MEASURES
Optic nerve length, ONH movement, and OC movement after time in microgravity.
RESULTS
Optic nerve length increased (0.80 ± 0.74 mm, P < 0.001), primarily reflecting forward ONH displacement (0.63 ± 0.53 mm, P < 0.001). The forward displacement was positively related to mission duration, preflight body weight, and clinical manifestations of SANS. We also detected upward displacement of the OC (0.39 ± 0.50 mm, P = 0.002), indicative of brain movement, but this observation could not be linked to SANS.
CONCLUSIONS
The spaceflight-induced optic nerve lengthening and anterior movement of the ONH support that SANS is caused by an altered pressure difference between the brain and the eye, leading to a forward push on the posterior of the eye. Body weight is a potential contributing risk factor. Direct assessment of intracranial pressure in space is required to verify the implicated mechanism behind the ocular findings in SANS.
Topics: Astronauts; Cohort Studies; Extraterrestrial Environment; Female; Humans; Intracranial Pressure; Magnetic Resonance Imaging; Male; Middle Aged; Optic Disk; Optic Nerve; Papilledema; Space Flight; Syndrome; Time Factors; Vision Disorders; Weightlessness
PubMed: 32659310
DOI: 10.1016/j.ophtha.2020.07.007 -
Annals of the Academy of Medicine,... Feb 2020
Topics: Glaucoma; Humans; Optic Disk
PubMed: 32246705
DOI: No ID Found -
Survey of Ophthalmology 2022Superior segmental optic nerve hypoplasia (SSONH) is a congenital condition characterized by developmental abnormalities of the superior optic disc and an... (Review)
Review
Superior segmental optic nerve hypoplasia (SSONH) is a congenital condition characterized by developmental abnormalities of the superior optic disc and an underappreciated differential diagnosis for glaucoma. The reported prevalence is less than 1%, although likely underestimated due to the difficulties with diagnosis. The exact pathophysiology of SSONH remains elusive, but a mechanism involving developmental attrition of retinal ganglion cells has been proposed, and maternal diabetes is recognized as a major risk factor. SSONH often is observed incidentally, and the patients typically are then evaluated for an acquired optic atrophy, often glaucoma because of the presence of inferior visual field defects. There are 4 characteristic signs of SSONH: superior entrance of the central retinal artery, superior disc pallor, superior peripapillary halo, and thinning of the superior peripapillary nerve fiber layer; however, the presence of these signs is variable. Optical coherence tomography can be helpful in distinguishing SSONH by demonstrating superonasal retinal nerve fiber layer thinning, as compared to the inferotemporal thinning seen in glaucoma, and an aberrant extension of retinal pigment epithelium over Bruch membrane. Overall, the prognosis of SSONH is favorable, with a non-progressive course. It is essential that ophthalmologists recognize and differentiate SSONH from glaucoma to avoid misdiagnosis and unnecessary treatment.
Topics: Glaucoma; Humans; Optic Disk; Optic Nerve Hypoplasia; Retinal Ganglion Cells; Tomography, Optical Coherence; Visual Field Tests
PubMed: 35189184
DOI: 10.1016/j.survophthal.2022.02.008 -
The British Journal of Ophthalmology Oct 2019Myopic eyes have an increased risk of glaucoma. However, glaucomatous changes in a myopic eye are often difficult to detect. Classic structural and functional... (Review)
Review
Myopic eyes have an increased risk of glaucoma. However, glaucomatous changes in a myopic eye are often difficult to detect. Classic structural and functional investigations to diagnose glaucoma may be confounded by myopia. Here, we identify some of the common pitfalls in interpreting these structural parameters, and the possible solutions that could be taken to overcome them. For instance, in myopic eyes, we discuss the limitations and potential sources of error when using neuroretinal rim parameters, and retinal nerve fibre layer and ganglion cell-inner plexiform layer thickness measurements. In addition, we also review new developments and potential adjuncts in structural imaging such as the assessment of the retinal nerve fibre layer texture, and the examination of the microcirculation of the optic nerve head using optical coherence tomography angiography. For the functional assessment of glaucoma, we discuss perimetric strategies that may aid in detecting characteristic visual field defects in myopic glaucoma. Ultimately, the evaluation of glaucoma in myopia requires a multimodal approach, to allow correlation between structural and functional assessments. This review provides overview on how to navigate this diagnostic dilemma.
Topics: Fluorescein Angiography; Glaucoma; Humans; Microcirculation; Myopia; Nerve Fibers; Optic Disk; Retinal Ganglion Cells; Tomography, Optical Coherence; Vision Disorders; Visual Fields
PubMed: 31040131
DOI: 10.1136/bjophthalmol-2018-313530