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The British Journal of Ophthalmology Jul 2023Spaceflight associated neuro-ocular syndrome (SANS) refers to a distinct constellation of ocular, neurological and neuroimaging findings observed in astronauts during... (Review)
Review
Spaceflight associated neuro-ocular syndrome (SANS) refers to a distinct constellation of ocular, neurological and neuroimaging findings observed in astronauts during and following long duration spaceflight. These ocular findings, to include optic disc oedema, posterior globe flattening, chorioretinal folds and hyperopic shifts, were first described by NASA in 2011. SANS is a potential risk to astronaut health and will likely require mitigation prior to planetary travel with prolonged exposures to microgravity. While the exact pathogenesis of SANS is not completely understood, several hypotheses have been proposed to explain this neuro-ocular phenomenon. In this paper, we briefly discuss the current hypotheses and contributing factors underlying SANS pathophysiology as well as analogues used to study SANS on Earth. We also review emerging potential countermeasures for SANS including lower body negative pressure, nutritional supplementation and translaminar pressure gradient modulation. Ongoing investigation within these fields will likely be instrumental in preparing and protecting astronaut vision for future spaceflight missions including deep space exploration.
Topics: Humans; Space Flight; Papilledema; Astronauts; Weightlessness
PubMed: 36690421
DOI: 10.1136/bjo-2022-322892 -
Eye (London, England) Nov 2021To determine if the presence or absence of retinal and choroidal folds on SD-OCT imaging can distinguish between mild papilloedema and pseudopapilledema.
PURPOSE
To determine if the presence or absence of retinal and choroidal folds on SD-OCT imaging can distinguish between mild papilloedema and pseudopapilledema.
DESIGN
Cross-sectional cohort study METHODS: Subjects with optic disc elevation (Frisen grades 1 and 2 only) were eligible to be enrolled prospectively. Pseudopapilledema was defined as a lack of change in optic disc appearance between two visits <6 months apart, and papilloedema was defined as change in optic disc appearance between two visits <6 months apart determined by review of fundus photographs by a masked neuro-ophthalmologist. Three masked neuro-ophthalmologists independently reviewed en face and axial optical coherence tomography (OCT) images of the optic nerve of the study subjects for the presence or absence of retinal and choroidal folds. Concordance was determined when there was agreement between at least 2 of the 3 observers.
RESULTS
Forty-five subjects (78 eyes) met inclusion criteria. There were 32 eyes with papilloedema and 46 eyes with pseudopapilledema. Choroidal and/or retinal folds were detected in 38% of eyes (12/32) with papilloedema and 19.6% of eyes (9/46) with pseudopapilledema. Post-hoc analyses eliminated six questionable cases of pseudopapilledema that had ancillary testing suggestive of elevated intracranial pressure and resulted in one remaining eye (2%) with more certain pseudopapilledema that was found to have folds. En face OCT imaging was more sensitive (71%) in detection of folds than axial OCT imaging (57%).
CONCLUSIONS
Choroidal and/or retinal folds on OCT are commonly observed in patients with mild papilloedema and are uncommon in those with pseudopapilledema. The presence of folds on OCT in patients presenting with disc elevation suggests papilloedema.
Topics: Cross-Sectional Studies; Eye Diseases, Hereditary; Humans; Nerve Fibers; Optic Nerve Diseases; Papilledema; Retinal Ganglion Cells; Tomography, Optical Coherence
PubMed: 33469131
DOI: 10.1038/s41433-020-01368-y -
Eye (London, England) Oct 2019Ophthalmic abnormalities including unilateral and bilateral optic disc edema, optic nerve sheath distention, globe flattening, choroidal folds, and hyperopic shifts have... (Review)
Review
Ophthalmic abnormalities including unilateral and bilateral optic disc edema, optic nerve sheath distention, globe flattening, choroidal folds, and hyperopic shifts have been observed in astronauts during and after long-duration spaceflight. An increased understanding of factors contributing to this syndrome, termed spaceflight-associated neuro-ocular syndrome, is currently a top priority for the ESA and NASA, especially since this medical obstacle could impact the visual health of astronauts as well as the success of future missions, including continued trips to the International Space Station, a return to the moon, or a future human mission to Mars. Currently, the exact mechanisms causing this neuro-ocular syndrome are not fully understood. In the present paper, we propose a hypothetical framework by which optic disc edema in astronauts may result, at least partly, from the forcing of perioptic cerebrospinal fluid into the optic nerve and optic disc along perivascular spaces surrounding the central retinal vessels, related to long-standing microgravity fluid shifts and variations in optic nerve sheath anatomy and compliance. Although this hypothesis remains speculative at the present time, future research in this area of investigation could not only provide exciting new insights into the mechanisms underlying microgravity-induced optic disc swelling but also offer opportunities to develop countermeasure strategies.
Topics: Astronauts; Blood-Retinal Barrier; Cerebrospinal Fluid; Choroid Diseases; Humans; Hyperopia; Intracranial Hypertension; Optic Nerve Diseases; Papilledema; Space Flight
PubMed: 31065103
DOI: 10.1038/s41433-019-0453-8 -
Eye (London, England) Aug 2020Idiopathic intracranial hypertension (IIH) is characterised by raised intracranial pressure (ICP) and papilloedema in the absence of an identifiable secondary cause... (Review)
Review
Idiopathic intracranial hypertension (IIH) is characterised by raised intracranial pressure (ICP) and papilloedema in the absence of an identifiable secondary cause typically occurring in young women with obesity. The impact is considerable with the potential for blindness, chronic disabling headaches, future risk of cardiovascular disease and marked healthcare utilisation. There have been marked advances in our understanding the pathophysiology of IIH including the role of androgen excess. Insight into pathophysiological underpinnings has arisen from astute clinical observations, studies, and an array of preclinical models. This article summarises the current literature pertaining to the pathophysiology of IIH. The current preclinical models relevant to gaining mechanistic insights into IIH are then discussed. In vitro and in vivo models which study CSF secretion and the effect of potentially pathogenic molecules have started to glean important mechanistic insights. These models are also useful to evaluate novel therapeutic targets to abrogate CSF secretion. Importantly, in vitro CSF secretion assays translate into relevant changes in ICP in vivo. Models of CSF absorption pertinent to IIH, are less well established but highly relevant and of future interest. There is no fully developed in vivo model of IIH but this remains an area of importance. Progress is being made to improve our understanding of the underlying aetiology in IIH including the characterisation of disease biomarkers and their mechanistic role in driving disease pathology. Preclinical models, used to evaluate IIH mechanisms are yielding important mechanistic insights. Further work to refine these techniques will provide translatable insights into disease aetiology.
Topics: Female; Humans; Intracranial Hypertension; Obesity; Papilledema; Pseudotumor Cerebri
PubMed: 31896803
DOI: 10.1038/s41433-019-0751-1 -
Nutrients Jul 2022Idiopathic intracranial hypertension (IIH) is a neurological disorder characterised by optic disc swelling secondary to raised intracranial pressure (ICP) of unknown... (Review)
Review
Idiopathic intracranial hypertension (IIH) is a neurological disorder characterised by optic disc swelling secondary to raised intracranial pressure (ICP) of unknown cause. Obesity is the most established and prevalent risk factor in developed countries. As obesogenic diets are high in calories and nutrient-poor, there may be associated nutritional deficiencies that contribute to the clinical presentation of IIH. Yet none, aside from iron deficiency, are currently included in the inclusion or exclusion criteria for the diagnosis of IIH. Our primary aim was to determine which micronutrient deficiencies, aside from iron deficiency, could present with optic disc swelling associated with or without intracranial hypertension that could potentially meet current IIH diagnostic criteria. To this end, we conducted a systematic search of articles published between 1 January 1980 and 18 December 2020 reporting cases of optic disc swelling associated with micronutrient deficiencies. In total, 65 cases met the eligibility criteria from initial searches: all were case reports and case series with a high risk of bias. Our findings suggest that patients with IIH or unexplained optic disc swelling ought to be screened, investigated, and treated for associated micronutrient deficiencies in vitamin A, B1 and B12; and weight loss interventions in IIH patients ought to promote better nutrition in addition to overall calorie restriction.
Topics: Humans; Intracranial Hypertension; Malnutrition; Micronutrients; Optic Disk; Papilledema; Pseudotumor Cerebri
PubMed: 35893919
DOI: 10.3390/nu14153068 -
Clinical & Experimental Ophthalmology Jan 2023Peripapillary hyperreflective ovoid mass-like structures (PHOMS) are a laterally bulging herniation of distended axons into the peripapillary region above the level of... (Review)
Review
Peripapillary hyperreflective ovoid mass-like structures (PHOMS) are a laterally bulging herniation of distended axons into the peripapillary region above the level of Bruch's membrane opening. Increased use of enhanced depth imaging-optical coherence tomography (EDI-OCT) in our evaluation of the optic nerve head (ONH) and greater recognition of the vast range of optic nerve pathologies with which PHOMS is associated provides convincing evidence that PHOMS is not just buried optic disc drusen (ODD) as previously described. The frequent coexistence of PHOMS with ODD, papilloedema, anterior ischaemic optic neuropathy, tilted optic disc syndrome, inflammatory demyelinating disorders and other diseases associated with axoplasmic stasis provides insight into its underlying pathophysiology. The present review will discuss the role of key imaging modalities in the differential diagnosis of PHOMS, explore the current literature on the relationship between PHOMS and common neuro-ophthalmic conditions, and highlight the gaps in our knowledge, with respect to disease classification and prognosis, to pave the way for future directions of research.
Topics: Humans; Optic Disk; Optic Disk Drusen; Papilledema; Tomography, Optical Coherence; Multimodal Imaging
PubMed: 36300762
DOI: 10.1111/ceo.14182 -
Journal of Neuro-ophthalmology : the... Mar 2015Very asymmetric papilledema in idiopathic intracranial hypertension (IIH) is rare, and few studies have dealt with this atypical presentation of IIH. Our aim was to...
BACKGROUND
Very asymmetric papilledema in idiopathic intracranial hypertension (IIH) is rare, and few studies have dealt with this atypical presentation of IIH. Our aim was to describe the clinical and radiologic features of patients with IIH and very asymmetric papilledema.
METHODS
We identified all adult patients from our IIH database with very asymmetric papilledema defined as a ≥2 modified Frisén grade difference between the 2 eyes. Demographic data and initial symptoms were collected, and all brain imaging studies performed at our institution were reviewed.
RESULTS
Of the 559 adult patients with definite IIH, 20 (3.6%; 95% confidence interval [CI], 2.3-5.6) had very asymmetric papilledema at initial evaluation. They were older (39 vs 30 years; P < 0.001), had lower cerebrospinal opening pressure (35.5 vs 36 cm of water; P = 0.03), and were more likely to be asymptomatic compared with patients with symmetric papilledema (27% vs 3%; P < 0.001). Visual fields were worse on the side of the highest-grade papilledema (P = 0.02). The bony optic canal was smaller on the side of the lowest-grade edema in all 8 patients (100%) in whom the imaging was sufficient for reliable measurements (P = 0.008).
CONCLUSIONS
IIH with very asymmetric papilledema is uncommon. Very asymmetric papilledema may result from differences in size of the bony optic canals, supporting the concept of compartmentation of the perioptic subarachnoid spaces.
Topics: Adolescent; Adult; Body Mass Index; Brain; Female; Humans; Magnetic Resonance Imaging; Male; Middle Aged; Papilledema; Pseudotumor Cerebri; Retrospective Studies; Statistics, Nonparametric; Tomography Scanners, X-Ray Computed; Visual Fields
PubMed: 25494197
DOI: 10.1097/WNO.0000000000000205 -
BMC Neurology Sep 2023Neuro-Behçet's disease (NBD), characterized by isolated intracranial hypertension, is a rarely encountered condition, especially in children. In this study, we describe... (Review)
Review
BACKGROUND
Neuro-Behçet's disease (NBD), characterized by isolated intracranial hypertension, is a rarely encountered condition, especially in children. In this study, we describe the treatment of a pediatric patient with NBD, who exhibited isolated intracranial pressure elevation as indicated by the initial manifestation of diplopia and physical examination finding of papilledema.
CASE PRESENTATION
An 8-year-old boy was admitted to the hospital with a confirmed diagnosis of Behçet's disease (BD) over eight months. The patient also presented with the symptom of diplopia for three days. The evaluation of the patient's nervous system did not reveal any apparent abnormalities. The measurement of cerebrospinal fluid pressure yielded a reading of 470 mm HO. The examination of the fundus indicated papilledema, and imaging scans revealed evidence of focal demyelination. The symptoms of the child showed alleviation after the administration of mannitol, methylprednisolone, and azathioprine. Furthermore, this study involved a comprehensive analysis of 18 cases of NBD with isolated intracranial hypertension, comprising one case reported herein and 17 cases from the literature review. Three cases were children, and an equal distribution of males and females 9:9 was noted. The average age at the onset of symptoms was 24.7 years (8-38 years). Headache (90%) was the most commonly reported clinical manifestation, followed by blurred vision or diplopia (80%). The ocular manifestations included papilledema (100%), abducent nerve paralysis (20%) and local eye hemorrhages in the retina (30%). Notably, 88.9% of these ocular manifestations were relieved or cured after treatment.
CONCLUSION
This study presents the first reported case of NBD with isolated intracranial hypertension in the pediatric population of China. In a child with Bechet's disease presenting with features of raised intracranial pressure, it is important to be aware of neuro Bechet's presenting with intracranial hypertension without other neurological abnormalities. This will help make early diagnosis, institute treatment and prevent sequelae resulting from untreated raised intracranial pressure.
Topics: Male; Female; Child; Humans; Young Adult; Adult; Papilledema; Behcet Syndrome; Diplopia; Intracranial Hypertension; Awareness
PubMed: 37749518
DOI: 10.1186/s12883-023-03392-3 -
Indian Pediatrics Oct 2020Pediatric papilledema is usually asymptomatic and is diagnosed on routine screening. We conducted a retrospective study to evaluate pediatric papilledema with respect to...
Pediatric papilledema is usually asymptomatic and is diagnosed on routine screening. We conducted a retrospective study to evaluate pediatric papilledema with respect to presentation, etiology and treatment at the neuroophthalmology clinic of a tertiary care eye institute.19 of the 24 children studied had Idiopathic intracranial hypertension.This study stresses upon the interdisciplinary approach for prompt diagnosis and treatment of papilledema.
Topics: Child; Humans; Papilledema; Pseudotumor Cerebri; Retrospective Studies; Tertiary Healthcare
PubMed: 33089814
DOI: No ID Found -
CMAJ : Canadian Medical Association... Jul 2008
Topics: Diagnostic Imaging; Humans; Ophthalmoscopes; Papilledema; Sensitivity and Specificity
PubMed: 18625992
DOI: 10.1503/cmaj.1080071