Abstract
Objective: Most of the astronauts onboard the International Space Station (ISS) develop visual impairment and ocular structural changes that are not fully reversible upon return to earth. Current understanding assumes that the so-called visual impairments/intracranial pressure (VIIP) syndrome is caused by cephalad vascular fluid shift. This study assesses the roles of cerebrospinal fluid (CSF) and intracranial pressure (ICP) in VIIP. Materials and methods: Seventeen astronauts, 9 who flew a short-duration mission on the space shuttle (14.1 days [SD 1.6]) and 7 who flew a long-duration mission on the ISS (188 days [SD 22]) underwent MRI of the brain and orbits to assess the pre-to-post spaceflight changes in four categories: VIIP severity measures: globe flattening and nerve protrusion; orbital and ventricular CSF volumes; cortical gray and white matter volumes; and MR-derived ICP (MRICP). Results: Significant pre-to-post-flight increase in globe flattening and optic nerve protrusion occurred only in the long-duration cohort (0.031 [SD 0.019] vs −0.001 [SD 0.006], and 0.025 [SD 0.013] vs 0.001 [SD 0.006]; p < 0.00002 respectively). The increased globe deformations were associated with significant increases in orbital and ventricular CSF volumes, but not with increased tissue vascular fluid content. Additionally, a moderate increase in MRICP of 6 mmHg was observed in only two ISS astronauts with large ocular structure changes. Conclusions: These findings are evidence for the primary role of CSF and a lesser role for intracranial cephalad fluid-shift in the formation of VIIP. VIIP is caused by a prolonged increase in orbital CSF spaces that compress the globes’ posterior pole, even without a large increase in ICP.
| Original language | English (US) |
|---|---|
| Title of host publication | Acta Neurochirurgica, Supplementum |
| Publisher | Springer-Verlag Wien |
| Pages | 215-219 |
| Number of pages | 5 |
| DOIs | |
| State | Published - Jan 1 2018 |
Publication series
| Name | Acta Neurochirurgica, Supplementum |
|---|---|
| Volume | 126 |
| ISSN (Print) | 0065-1419 |
| ISSN (Electronic) | 2197-8395 |
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Keywords
- Cephalad fluid shift
- Globe flattening
- Optic nerve protrusion
- Quantitative MRI
- Visual impairment/intracranial pressure syndrome
ASJC Scopus subject areas
- Surgery
- Clinical Neurology
Cite this
Spaceflight-induced visual impairment and globe deformations in astronauts are linked to orbital cerebrospinal fluid volume increase. / Alperin, Noam; Bagci, Ahmet M.
Acta Neurochirurgica, Supplementum. Springer-Verlag Wien, 2018. p. 215-219 (Acta Neurochirurgica, Supplementum; Vol. 126).Research output: Chapter in Book/Report/Conference proceeding › Chapter
}
TY - CHAP
T1 - Spaceflight-induced visual impairment and globe deformations in astronauts are linked to orbital cerebrospinal fluid volume increase
AU - Alperin, Noam
AU - Bagci, Ahmet M.
PY - 2018/1/1
Y1 - 2018/1/1
N2 - Objective: Most of the astronauts onboard the International Space Station (ISS) develop visual impairment and ocular structural changes that are not fully reversible upon return to earth. Current understanding assumes that the so-called visual impairments/intracranial pressure (VIIP) syndrome is caused by cephalad vascular fluid shift. This study assesses the roles of cerebrospinal fluid (CSF) and intracranial pressure (ICP) in VIIP. Materials and methods: Seventeen astronauts, 9 who flew a short-duration mission on the space shuttle (14.1 days [SD 1.6]) and 7 who flew a long-duration mission on the ISS (188 days [SD 22]) underwent MRI of the brain and orbits to assess the pre-to-post spaceflight changes in four categories: VIIP severity measures: globe flattening and nerve protrusion; orbital and ventricular CSF volumes; cortical gray and white matter volumes; and MR-derived ICP (MRICP). Results: Significant pre-to-post-flight increase in globe flattening and optic nerve protrusion occurred only in the long-duration cohort (0.031 [SD 0.019] vs −0.001 [SD 0.006], and 0.025 [SD 0.013] vs 0.001 [SD 0.006]; p < 0.00002 respectively). The increased globe deformations were associated with significant increases in orbital and ventricular CSF volumes, but not with increased tissue vascular fluid content. Additionally, a moderate increase in MRICP of 6 mmHg was observed in only two ISS astronauts with large ocular structure changes. Conclusions: These findings are evidence for the primary role of CSF and a lesser role for intracranial cephalad fluid-shift in the formation of VIIP. VIIP is caused by a prolonged increase in orbital CSF spaces that compress the globes’ posterior pole, even without a large increase in ICP.
AB - Objective: Most of the astronauts onboard the International Space Station (ISS) develop visual impairment and ocular structural changes that are not fully reversible upon return to earth. Current understanding assumes that the so-called visual impairments/intracranial pressure (VIIP) syndrome is caused by cephalad vascular fluid shift. This study assesses the roles of cerebrospinal fluid (CSF) and intracranial pressure (ICP) in VIIP. Materials and methods: Seventeen astronauts, 9 who flew a short-duration mission on the space shuttle (14.1 days [SD 1.6]) and 7 who flew a long-duration mission on the ISS (188 days [SD 22]) underwent MRI of the brain and orbits to assess the pre-to-post spaceflight changes in four categories: VIIP severity measures: globe flattening and nerve protrusion; orbital and ventricular CSF volumes; cortical gray and white matter volumes; and MR-derived ICP (MRICP). Results: Significant pre-to-post-flight increase in globe flattening and optic nerve protrusion occurred only in the long-duration cohort (0.031 [SD 0.019] vs −0.001 [SD 0.006], and 0.025 [SD 0.013] vs 0.001 [SD 0.006]; p < 0.00002 respectively). The increased globe deformations were associated with significant increases in orbital and ventricular CSF volumes, but not with increased tissue vascular fluid content. Additionally, a moderate increase in MRICP of 6 mmHg was observed in only two ISS astronauts with large ocular structure changes. Conclusions: These findings are evidence for the primary role of CSF and a lesser role for intracranial cephalad fluid-shift in the formation of VIIP. VIIP is caused by a prolonged increase in orbital CSF spaces that compress the globes’ posterior pole, even without a large increase in ICP.
KW - Cephalad fluid shift
KW - Globe flattening
KW - Optic nerve protrusion
KW - Quantitative MRI
KW - Visual impairment/intracranial pressure syndrome
UR - http://www.scopus.com/inward/record.url?scp=85042934629&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85042934629&partnerID=8YFLogxK
U2 - 10.1007/978-3-319-65798-1_44
DO - 10.1007/978-3-319-65798-1_44
M3 - Chapter
C2 - 29492564
AN - SCOPUS:85042934629
T3 - Acta Neurochirurgica, Supplementum
SP - 215
EP - 219
BT - Acta Neurochirurgica, Supplementum
PB - Springer-Verlag Wien
ER -