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Masood MT, Wang JWW, Zoumi EA, Jain K, Suh A, Ong J, Waisberg E, Masalkhi M, Lee AG. Impedance threshold device as a countermeasure for spaceflight associated neuro-ocular syndrome (SANS): Mitigating mechanisms in proposed pathophysiology. LIFE SCIENCES IN SPACE RESEARCH 2024; 42:99-107. [PMID: 39067998 DOI: 10.1016/j.lssr.2024.06.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Revised: 05/31/2024] [Accepted: 06/05/2024] [Indexed: 07/30/2024]
Abstract
Long-duration spaceflight (LDSF) is associated with unique hazards and linked with numerous human health risks including Spaceflight Associated Neuro-ocular Syndrome (SANS). The proposed mechanisms for SANS include microgravity induced cephalad fluid shift and increased Intracranial Pressure (ICP). SANS is a disorder seen only after LDSF and has no direct terrestrial pathologic counterpart as the zero G environment cannot be completely replicated on Earth. Head-down tilt, bed rest studies however have been used as a terrestrial analog and produce the cephalad fluid shift. Some proposed countermeasures for SANS include vasoconstrictive thigh cuffs and lower body negative pressure. Another potential researched countermeasure is the impedance threshold device (ITD) which can reduce ICP. We review the mechanisms of the ITD and its potential use as a countermeasure for SANS.
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Affiliation(s)
| | | | | | | | - Alex Suh
- Tulane University School of Medicine, New Orleans, LA, United States
| | - Joshua Ong
- Department of Ophthalmology and Visual Sciences, University of Michigan Kellogg Eye Center, Ann Arbor, Michigan, United States
| | - Ethan Waisberg
- Department of Ophthalmology, University of Cambridge, Cambridge, United Kingdom
| | - Mouayad Masalkhi
- University College Dublin School of Medicine, Belfield, Dublin, Ireland
| | - Andrew G Lee
- Center for Space Medicine, Baylor College of Medicine, Houston, Texas, United States; Department of Ophthalmology, Blanton Eye Institute, Houston Methodist Hospital, Houston, Texas, United States; The Houston Methodist Research Institute, Houston Methodist Hospital, Houston, Texas, United States; Departments of Ophthalmology, Neurology, and Neurosurgery, Weill Cornell Medicine, New York, New York, United States; Department of Ophthalmology, University of Texas Medical Branch, Galveston, Texas, United States; University of Texas MD Anderson Cancer Center, Houston, Texas, United States; Texas A&M College of Medicine, Bryan, Texas, United States; Department of Ophthalmology, The University of Iowa Hospitals and Clinics, Iowa City, Iowa, United States.
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Brunstetter TJ, Zwart SR, Brandt K, Brown DM, Clemett SJ, Douglas GL, Gibson CR, Laurie SS, Lee AG, Macias BR, Mader TH, Mason SS, Meir JU, Morgan AR, Nelman M, Patel N, Sams C, Suresh R, Tarver W, Tsung A, Van Baalen MG, Smith SM. Severe Spaceflight-Associated Neuro-Ocular Syndrome in an Astronaut With 2 Predisposing Factors. JAMA Ophthalmol 2024:2821259. [PMID: 39052244 PMCID: PMC11273286 DOI: 10.1001/jamaophthalmol.2024.2385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2024] [Accepted: 05/09/2024] [Indexed: 07/27/2024]
Abstract
Importance Understanding potential predisposing factors associated with spaceflight-associated neuro-ocular syndrome (SANS) may influence its management. Objective To describe a severe case of SANS associated with 2 potentially predisposing factors. Design, Setting, and Participants Ocular testing of and blood collections from a female astronaut were completed preflight, inflight, and postflight in the setting of the International Space Station (ISS). Exposure Weightlessness throughout an approximately 6-month ISS mission. Mean carbon dioxide (CO2) partial pressure decreased from 2.6 to 1.3 mm Hg weeks before the astronaut's flight day (FD) 154 optical coherence tomography (OCT) session. In response to SANS, 4 B-vitamin supplements (vitamin B6, 100 mg; L-methylfolate, 5 mg; vitamin B12, 1000 μg; and riboflavin, 400 mg) were deployed, unpacked on FD153, consumed daily through FD169, and then discontinued due to gastrointestinal discomfort. Main Outcomes and Measures Refraction, distance visual acuity (DVA), optic nerve, and macular assessment on OCT. Results Cycloplegic refraction was -1.00 diopter in both eyes preflight and +0.50 - 0.25 × 015 in the right eye and +1.00 diopter in the left eye 3 days postflight. Uncorrected DVA was 20/30 OU preflight, 20/16 or better by FD90, and 20/15 OU 3 days postflight. Inflight peripapillary total retinal thickness (TRT) peaked between FD84 and FD126 (right eye, 401 μm preflight, 613 μm on FD84; left eye, 404 μm preflight, 636 μm on FD126), then decreased. Peripapillary choroidal folds, quantified by surface roughness, peaked at 12.7 μm in the right eye on FD154 and 15.0 μm in the left eye on FD126, then decreased. Mean choroidal thickness increased throughout the mission. Genetic analyses revealed 2 minor alleles for MTRR 66 and 2 major alleles for SHMT1 1420 (ie, 4 of 4 SANS risk alleles). One-week postflight, lumbar puncture opening pressure was normal, at 19.4 cm H2O. Conclusions and Relevance To the authors' knowledge, no other report of SANS documented as large of a change in peripapillary TRT or hyperopic shift during a mission as in this astronaut, and this was only 1 of 4 astronauts to experience chorioretinal folds approaching the fovea. This case showed substantial inflight improvement greater than the sensitivity of the measure, possibly associated with B-vitamin supplementation and/or reduction in cabin CO2. However, as a single report, such improvement could be coincidental to these interventions, warranting further evaluation.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Andrew G. Lee
- Blanton Eye Institute, Houston Methodist Hospital, Houston, Texas
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Hall EA, Whittle RS, Diaz-Artiles A. Ocular perfusion pressure is not reduced in response to lower body negative pressure. NPJ Microgravity 2024; 10:67. [PMID: 38851800 PMCID: PMC11162494 DOI: 10.1038/s41526-024-00404-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2023] [Accepted: 05/16/2024] [Indexed: 06/10/2024] Open
Abstract
Lower body negative pressure (LBNP) has been proposed as a countermeasure to mitigate the cephalad fluid shift occurring during spaceflight, which may be associated with the development of Spaceflight Associated Neuro-ocular Syndrome (SANS). This study quantifies the effect of LBNP on intraocular pressure (IOP), mean arterial pressure at eye level (MAPeye), and ocular perfusion pressure (OPP). Twenty-four subjects (12 male, 12 female) were subjected to graded LBNP in 0° supine and 15° head-down tilt (HDT) postures from 0 mmHg to -50 mmHg in 10 mmHg increments. IOP decreased significantly with LBNP pressure in 0° supine (by 0.7 ± 0.09 mmHg per 10 mmHg LBNP pressure, p < 0.001) and in 15° HDT (by 1.0 ± 0.095 mmHg per 10 mmHg of LBNP pressure, p < 0.001). MAPeye significantly decreased by 0.9 ± 0.4 mmHg per 10 mmHg of LBNP pressure in 0° supine (p = 0.016) but did not significantly change with LBNP in 15° HDT (p = 0.895). OPP did not significantly change with LBNP in 0° supine (p = 0.539) but it significantly increased in 15° HDT at 1.0 ± 0.3 mmHg per 10 mmHg of LBNP pressure (p = 0.010). Sex did not have a significant effect on OPP, MAPeye, or IOP in any condition. In 15° HDT, the reduction in IOP during increasing negative pressure, combined with the relatively constant MAPeye, led to the increase in OPP. Furthermore, results suggest that LBNP, while effective in reducing IOP, is not effective in reducing OPP across all postures investigated.
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Affiliation(s)
- Eric A Hall
- Department of Biomedical Engineering, Texas A&M University, College Station, TX, USA
- School of Engineering Medicine (EnMed), Texas A&M University, Houston, TX, USA
| | - Richard S Whittle
- Department of Mechanical and Aerospace Engineering, University of California Davis, Davis, CA, USA
- Department of Aerospace Engineering, Texas A&M University, College Station, TX, USA
| | - Ana Diaz-Artiles
- Department of Aerospace Engineering, Texas A&M University, College Station, TX, USA.
- Department of Kinesiology and Sport Management, Texas A&M University, College Station, TX, USA.
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Christian KH, Petitti C, Oretga-Schwartz K, Mulder E, Noppe A, von der Wiesche M, Stern C, Young M, Macias BR, Laurie SS, Lovering AT. Development of optic disc edema during 30 days of hypercapnic head-down tilt bed rest is associated with short sleep duration and blunted temperature amplitude. J Appl Physiol (1985) 2024; 136:753-763. [PMID: 38357726 DOI: 10.1152/japplphysiol.00211.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 02/07/2024] [Accepted: 02/07/2024] [Indexed: 02/16/2024] Open
Abstract
Sleep and circadian temperature disturbances occur with spaceflight and may, in part, result from the chronically elevated carbon dioxide (CO2) levels on the international space station. Impaired sleep may contribute to decreased glymphatic clearance and, when combined with the chronic headward fluid shift during actual spaceflight or the spaceflight analog head-down tilt bed rest (HDTBR), may contribute to the development of optic disc edema. We determined if strict HDTBR combined with mildly elevated CO2 levels influenced sleep and core temperature and was associated with the development of optic disc edema. Healthy participants (5 females) aged 25-50 yr, underwent 30 days of strict 6° HDTBR with ambient Pco2 = 4 mmHg. Measures of sleep, 24-h core temperature, overnight transcutaneous CO2, and Frisén grade edema were made pre-HDTBR, on HDTBR days 4, 17, 28, and post-HDTBR days 4 and 10. During all HDTBR time points, sleep, core temperature, and overnight transcutaneous CO2 were not different than the pre-HDTBR measurements. However, independent of the HDTBR intervention, the odds ratios {mean [95% confidence interval (CI)]} for developing Frisén grade optic disc edema were statistically significant for each hour below the mean total sleep time (2.2 [1.1-4.4]) and stage 2 nonrapid eye movement (NREM) sleep (4.8 [1.3-18.6]), and above the mean for wake after sleep onset (3.6 [1.2-10.6]) and for each 0.1°C decrease in core temperature amplitude below the mean (4.0 [1.4-11.7]). These data suggest that optic disc edema occurring during HDTBR was more likely to occur in those with short sleep duration and/or blunted temperature amplitude.NEW & NOTEWORTHY We determined that sleep and 24-h core body temperature were unaltered by 30 days exposure to the spaceflight analog strict 6° head-down tilt bed rest (HDTBR) in a 0.5% CO2 environment. However, shorter sleep duration, greater wake after sleep onset, and lower core temperature amplitude present throughout the study were associated with the development of optic disc edema, a key finding of spaceflight-associated neuro-ocular syndrome.
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Affiliation(s)
- Kate H Christian
- Department of Human Physiology, University of Oregon, Eugene, Oregon, United States
| | - Carla Petitti
- PeaceHealth Sleep Disorders Center, Springfield, Oregon, United States
| | - Kyra Oretga-Schwartz
- Department of Human Physiology, University of Oregon, Eugene, Oregon, United States
| | - Edwin Mulder
- German Aerospace Center, Institute of Aerospace Medicine, Cologne, Germany
| | - Alexandra Noppe
- German Aerospace Center, Institute of Aerospace Medicine, Cologne, Germany
| | | | - Claudia Stern
- German Aerospace Center, Institute of Aerospace Medicine, Cologne, Germany
| | | | | | | | - Andrew T Lovering
- Department of Human Physiology, University of Oregon, Eugene, Oregon, United States
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Tomsia M, Cieśla J, Śmieszek J, Florek S, Macionga A, Michalczyk K, Stygar D. Long-term space missions' effects on the human organism: what we do know and what requires further research. Front Physiol 2024; 15:1284644. [PMID: 38415007 PMCID: PMC10896920 DOI: 10.3389/fphys.2024.1284644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Accepted: 01/22/2024] [Indexed: 02/29/2024] Open
Abstract
Space has always fascinated people. Many years have passed since the first spaceflight, and in addition to the enormous technological progress, the level of understanding of human physiology in space is also increasing. The presented paper aims to summarize the recent research findings on the influence of the space environment (microgravity, pressure differences, cosmic radiation, etc.) on the human body systems during short-term and long-term space missions. The review also presents the biggest challenges and problems that must be solved in order to extend safely the time of human stay in space. In the era of increasing engineering capabilities, plans to colonize other planets, and the growing interest in commercial space flights, the most topical issues of modern medicine seems to be understanding the effects of long-term stay in space, and finding solutions to minimize the harmful effects of the space environment on the human body.
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Affiliation(s)
- Marcin Tomsia
- Department of Forensic Medicine and Forensic Toxicology, Faculty of Medical Sciences in Katowice, Medical University of Silesia, Katowice, Poland
| | - Julia Cieśla
- School of Medicine in Katowice, Medical University of Silesia, Katowice, Poland
| | - Joanna Śmieszek
- School of Medicine in Katowice, Medical University of Silesia, Katowice, Poland
| | - Szymon Florek
- School of Medicine in Katowice, Medical University of Silesia, Katowice, Poland
| | - Agata Macionga
- School of Medicine in Katowice, Medical University of Silesia, Katowice, Poland
| | - Katarzyna Michalczyk
- Department of Physiology, Faculty of Medical Sciences in Zabrze, Medical University of Silesia, Katowice, Poland
| | - Dominika Stygar
- Department of Physiology, Faculty of Medical Sciences in Zabrze, Medical University of Silesia, Katowice, Poland
- SLU University Animal Hospital, Swedish University of Agricultural Sciences, Uppsala, Sweden
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6
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Masís Solano M, Bélanger Nzakimuena C, Dumas R, Lesk MR, Costantino S. Ocular rigidity and choroidal thickness changes in response to microgravity: A case study. Am J Ophthalmol Case Rep 2023; 32:101940. [PMID: 37860670 PMCID: PMC10582271 DOI: 10.1016/j.ajoc.2023.101940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2023] [Revised: 10/03/2023] [Accepted: 10/05/2023] [Indexed: 10/21/2023] Open
Abstract
Purpose To evaluate ocular rigidity and choroidal thickness changes in response to microgravity and the Valsalva maneuver in a private astronaut. Methods Ophthalmological examination and Optical Coherence Tomography were performed before, during, and after space flight. Choroidal thickness was measured at all time points at rest and during the Valsalva maneuver. Ocular rigidity was obtained before and after flight using a non-invasive method enhanced with deep learning-based choroid segmentation. Results Ocular rigidity decreased after space flight compared to baseline. There was an increase in average choroidal thickness during the Valsalva maneuver compared to the resting condition before, during, and after space flight, and such increase was greater when the Valsalva maneuver was performed during space flight. Conclusions and importance The data indicates biomechanical changes to ocular tissues because of space flight and greater choroidal thickness increase. The findings could lead to a better understanding of space flight-associated neuro-ocular syndrome and may have repercussions for short duration missions in a nascent industry.
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Affiliation(s)
- Marissé Masís Solano
- Département d’Ophtalmologie, Université de Montréal, Canada
- Centre de recherche de l'Hôpital Maisonneuve-Rosemont, Canada
| | | | | | - Mark R. Lesk
- Département d’Ophtalmologie, Université de Montréal, Canada
- Centre de recherche de l'Hôpital Maisonneuve-Rosemont, Canada
| | - Santiago Costantino
- Département d’Ophtalmologie, Université de Montréal, Canada
- Centre de recherche de l'Hôpital Maisonneuve-Rosemont, Canada
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7
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Milner DC, Subramanian PS. Insights into spaceflight-associated neuro-ocular syndrome with review of intraocular and orbital findings. Curr Opin Ophthalmol 2023; 34:493-499. [PMID: 37729662 DOI: 10.1097/icu.0000000000001000] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/22/2023]
Abstract
PURPOSE OF REVIEW Spaceflight-associated neuro-ocular syndrome (SANS) remains a phenomenological term, and advances in ophthalmic imaging as well as new insights from ground-based experiments have given support to new theories of how SANS develops and what may be done to counter it. RECENT FINDINGS SANS has been postulated to arise from elevated intracranial pressure (ICP) during long-duration spaceflight (LDSF). However, recent work has shown that acute microgravity exposure does not increase ICP, and the effect of cephalad fluid shifts on ICP in microgravity remain unknown. In addition, structural imaging of the retina and optic nerve show changes after LDSF that are distinct from findings in terrestrial patients with elevated ICP. Since astronauts have not reported symptoms that would be expected with chronic ICP elevation, new theories that orbital and/or intracranial venous pressure may be the primary contributors to the development of SANS. SUMMARY Research has been filling knowledge gaps that exist regarding the cause(s) of SANS, and these advances are crucial steps in the effort to design countermeasures that will be required before human deep space exploration missions can be undertaken.
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Affiliation(s)
- Dallin C Milner
- Sue Anschutz-Rodgers University of Colorado Eye Center and Department of Ophthalmology
| | - Prem S Subramanian
- Sue Anschutz-Rodgers University of Colorado Eye Center and Department of Ophthalmology
- Department of Neurology
- Department of Neurosurgery, University of Colorado School of Medicine, Aurora, Colorado
- Department of Surgery (Division of Ophthalmology), Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
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8
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Ong J, Mader TH, Gibson CR, Mason SS, Lee AG. Spaceflight associated neuro-ocular syndrome (SANS): an update on potential microgravity-based pathophysiology and mitigation development. Eye (Lond) 2023; 37:2409-2415. [PMID: 37072472 PMCID: PMC10397180 DOI: 10.1038/s41433-023-02522-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 03/21/2023] [Accepted: 04/04/2023] [Indexed: 04/20/2023] Open
Abstract
Long-duration spaceflight is associated with neurologic and ophthalmic clinical and imaging findings in astronauts termed spaceflight associated neuro-ocular syndrome (SANS). These microgravity-induced findings have been well documented by the National Aeronautics and Space Administration (NASA) and are clearly a potential risk for future human space exploration. The underlying pathogenesis of SANS is not well understood, although multiple hypotheses have emerged. Terrestrial analogues and potential countermeasures have also been studied to further understand and potentially mitigate SANS. In this manuscript, we review the current understanding of SANS, discuss the prevailing hypotheses for pathogenesis, and describe current developments in terrestrial analogues and potential countermeasures for SANS.
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Affiliation(s)
- Joshua Ong
- Michigan Medicine, University of Michigan, Ann Arbor, MI, USA
| | | | - C Robert Gibson
- KBR, NASA Johnson Space Center, Houston, TX, USA
- South Shore Eye Center, League City, TX, USA
| | | | - Andrew G Lee
- Department of Ophthalmology, Blanton Eye Institute, Houston Methodist Hospital, Houston, TX, USA.
- Center for Space Medicine, Baylor College of Medicine, Houston, TX, USA.
- The Houston Methodist Research Institute, Houston Methodist Hospital, Houston, TX, USA.
- Departments of Ophthalmology, Neurology, and Neurosurgery, Weill Cornell Medicine, New York, NY, USA.
- Department of Ophthalmology, University of Texas Medical Branch, Galveston, TX, USA.
- University of Texas MD Anderson Cancer Center, Houston, TX, USA.
- Texas A&M College of Medicine, Bryan, TX, USA.
- Department of Ophthalmology, The University of Iowa Hospitals and Clinics, Iowa City, IA, USA.
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9
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Grigoryan EN. Impact of Microgravity and Other Spaceflight Factors on Retina of Vertebrates and Humans In Vivo and In Vitro. Life (Basel) 2023; 13:1263. [PMID: 37374046 DOI: 10.3390/life13061263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 05/20/2023] [Accepted: 05/25/2023] [Indexed: 06/29/2023] Open
Abstract
Spaceflight (SF) increases the risk of developmental, regenerative, and physiological disorders in animals and humans. Astronauts, besides bone loss, muscle atrophy, and cardiovascular and immune system alterations, undergo ocular disorders affecting posterior eye tissues, including the retina. Few studies revealed abnormalities in the development and changes in the regeneration of eye tissues in lower vertebrates after SF and simulated microgravity. Under microgravity conditions, mammals show disturbances in the retinal vascular system and increased risk of oxidative stress that can lead to cell death in the retina. Animal studies provided evidence of gene expression changes associated with cellular stress, inflammation, and aberrant signaling pathways. Experiments using retinal cells in microgravity-modeling systems in vitro additionally indicated micro-g-induced changes at the molecular level. Here, we provide an overview of the literature and the authors' own data to assess the predictive value of structural and functional alterations for developing countermeasures and mitigating the SF effects on the human retina. Further emphasis is given to the importance of animal studies on the retina and other eye tissues in vivo and retinal cells in vitro aboard spacecraft for understanding alterations in the vertebrate visual system in response to stress caused by gravity variations.
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Affiliation(s)
- Eleonora N Grigoryan
- Koltzov Institute of Developmental Biology, Russian Academy of Sciences, 119334 Moscow, Russia
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10
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Ferguson CR, Pardon LP, Laurie SS, Young MH, Gibson CR, Brunstetter TJ, Tarver WJ, Mason SS, Sibony PA, Macias BR. Incidence and Progression of Chorioretinal Folds During Long-Duration Spaceflight. JAMA Ophthalmol 2023; 141:168-175. [PMID: 36602790 PMCID: PMC9857718 DOI: 10.1001/jamaophthalmol.2022.5681] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Accepted: 11/06/2022] [Indexed: 01/06/2023]
Abstract
Importance The primary contributing factor for development of chorioretinal folds during spaceflight is unknown. Characterizing fold types that develop and tracking their progression may provide insight into the pathophysiology of spaceflight-associated neuro-ocular syndrome and elucidate the risk of fold progression for future exploration-class missions exceeding 12 months in duration. Objective To determine the incidence and presentation of chorioretinal folds in long-duration International Space Station crew members and objectively quantify the progression of choroidal folds during spaceflight. Design, Setting, and Participants In this retrospective cohort study, optical coherence tomography scans of the optic nerve head and macula of crew members completing long-duration spaceflight missions were obtained on Earth prior to spaceflight and during flight. A panel of experts examined the scans for the qualitative presence of chorioretinal folds. Peripapillary total retinal thickness was calculated to identify eyes with optic disc edema, and choroidal folds were quantified based on surface roughness within macular and peripapillary regions of interest. Interventions or Exposures Spaceflight missions ranging 6 to 12 months. Main Outcomes and Measures Incidence of peripapillary wrinkles, retinal folds, and choroidal folds; peripapillary total retinal thickness; and Bruch membrane surface roughness. Results A total of 36 crew members were analyzed (mean [SD] age, 46 [6] years; 7 [19%] female). Chorioretinal folds were observed in 12 of 72 eyes (17%; 6 crew members). In eyes with early signs of disc edema, 10 of 42 (24%) had choroidal folds, 4 of 42 (10%) had inner retinal folds, and 2 of 42 (5%) had peripapillary wrinkles. Choroidal folds were observed in all eyes with retinal folds and peripapillary wrinkles. Macular choroidal folds developed in 7 of 12 eyes (4 of 6 crew members) with folds and progressed with mission duration; these folds extended into the fovea in 6 eyes. Circumpapillary choroidal folds developed predominantly superior, nasal, and inferior to the optic nerve head and increased in prevalence and severity with mission duration. Conclusions and Relevance Choroidal folds were the most common fold type to develop during spaceflight; this differs from reports in idiopathic intracranial hypertension, suggesting differences in the mechanisms underlying fold formation. Quantitative measures demonstrate the development and progression of choroidal folds during weightlessness, and these metrics may help to assess the efficacy of spaceflight-associated neuro-ocular syndrome countermeasures.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Patrick A. Sibony
- Department of Ophthalmology, Stony Brook Medicine, Stony Brook, New York
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11
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Heath Jeffery RC, Chen FK. Peripapillary hyperreflective ovoid mass-like structures: Multimodal imaging-A review. Clin Exp Ophthalmol 2023; 51:67-80. [PMID: 36300762 PMCID: PMC10099767 DOI: 10.1111/ceo.14182] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 10/04/2022] [Accepted: 10/21/2022] [Indexed: 11/07/2022]
Abstract
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.
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Affiliation(s)
- Rachael C Heath Jeffery
- Centre for Ophthalmology and Visual Science (incorporating Lions Eye Institute), The University of Western Australia, Nedlands, Western Australia, Australia.,Royal Victorian Eye and Ear Hospital (Centre for Eye Research Australia), East Melbourne, Victoria, Australia
| | - Fred K Chen
- Centre for Ophthalmology and Visual Science (incorporating Lions Eye Institute), The University of Western Australia, Nedlands, Western Australia, Australia.,Royal Victorian Eye and Ear Hospital (Centre for Eye Research Australia), East Melbourne, Victoria, Australia.,Ophthalmology, Department of Surgery, The University of Melbourne, East Melbourne, Victoria, Australia.,Department of Ophthalmology, Royal Perth Hospital, Western Australia, Australia
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12
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Taniguchi-Shinojima A. Possible Mitigating Factors in Optic Disc Edema During Spaceflight. JAMA Ophthalmol 2022; 140:1200-1201. [PMID: 36301529 DOI: 10.1001/jamaophthalmol.2022.4463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- Ari Taniguchi-Shinojima
- Laboratory of Photobiology, Keio University School of Medicine, Tokyo, Shinjuku-ku, Japan.,Department of Ophthalmology, Keio University School of Medicine, Shinanomachi, Tokyo, Shinjuku-ku, Japan
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13
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Pardon LP, Greenwald SH, Ferguson CR, Patel NB, Young M, Laurie SS, Macias BR. Identification of Factors Associated With the Development of Optic Disc Edema During Spaceflight. JAMA Ophthalmol 2022; 140:1193-1200. [PMID: 36301519 PMCID: PMC9614681 DOI: 10.1001/jamaophthalmol.2022.4396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Accepted: 09/01/2022] [Indexed: 01/12/2023]
Abstract
Importance Approximately 70% of crew members who complete long-duration missions to the International Space Station develop signs of optic disc edema, a hallmark finding of spaceflight-associated neuro-ocular syndrome. The onset and magnitude of edema differ across individuals, and the reason for this variability remains unknown. Identifying risk factors for spaceflight-induced disc edema is important because this condition may become more severe during extended-duration missions to the moon and Mars and could be associated with irreversible vision loss. Objective To assess whether preflight indicators of crowded optic nerve head morphology, other ocular measures (such as choroid thickness and axial length), body weight, body mass index, sex, age, and previous flight experience are associated with optic disc edema development. Design, Setting, and Participants This cohort study analyzed ocular, body weight, and demographic data collected from 31 US and international crew members before, during, and after spaceflight at the NASA Johnson Space Center and International Space Station. Ocular factors assessed included preflight and in-flight peripapillary total retinal thickness, minimum rim width, optic cup volume, mean cup depth, mean cup width, cup-disc ratio, Bruch membrane opening area, retinal nerve fiber layer thickness, choroid thickness, axial length, and refractive error. In addition, body weight, body mass index, sex, age, and previous spaceflight experience were assessed for associations with optic disc edema development. The data were analyzed from August 2021 to June 2022. Exposure Approximately 6 to 12 months of spaceflight. Main Outcomes and Measures In-flight increases in peripapillary total retinal thickness. Linear mixed models were used to assess for associations between a wide range of risk factors and in-flight increases in peripapillary total retinal thickness, which is a sensitive objective measure for detecting optic disc edema. Results This study included 31 International Space Station crew members with a mean (SD) age of 46.9 (6.0) years (25 men [80.6%]). During spaceflight, mean (SE) peripapillary total retinal thickness increased from 392.0 (5.8) μm to 430.2 (9.6) μm (P < .001), and greater individual changes were associated with smaller preflight cup volume (slope [SE], -62.8 [18.9]; P = .002), shallower preflight cup depth (slope [SE], -0.11 [0.03]; P < .001), and narrower preflight cup width (slope [SE], -0.03 [0.01]; P = .03). No associations were observed between changes in peripapillary total retinal thickness and any other variable evaluated. Conclusions and Relevance Findings of this cohort study suggest that smaller optic cup morphology may be associated with optic disc edema development during spaceflight. Crew members with this cup profile may benefit from enhanced ophthalmic monitoring during spaceflight and use of countermeasures against spaceflight-associated neuro-ocular syndrome.
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Affiliation(s)
| | | | | | | | - Millennia Young
- National Aeronautics and Space Administration Johnson Space Center, Houston, Texas
| | | | - Brandon R. Macias
- National Aeronautics and Space Administration Johnson Space Center, Houston, Texas
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Wostyn P, Gibson CR, Mader TH. The Enigma of the Posterior Displacement of the Bruch Membrane Opening During Spaceflight. JAMA Ophthalmol 2022; 140:1029. [DOI: 10.1001/jamaophthalmol.2022.3637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Peter Wostyn
- Department of Psychiatry, PC Sint-Amandus, Beernem, Belgium
| | - Charles Robert Gibson
- South Shore Eye Center, League City, Texas
- KBR, NASA Space Medicine Operations Division, Houston, Texas
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Pardon LP, Ferguson CR, Laurie SS. The Enigma of the Posterior Displacement of the Bruch Membrane Opening During Spaceflight—Reply. JAMA Ophthalmol 2022; 140:1029-1030. [DOI: 10.1001/jamaophthalmol.2022.3634] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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Correction to Data Points in Figure. JAMA Ophthalmol 2022; 140:912. [PMID: 35951337 DOI: 10.1001/jamaophthalmol.2022.3302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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