T. Russomano* T. Russomano* L. F. B. Chotgues* L. F. B. Chotgues* O. A. Lima de Sá* O. A. Lima de Sá* M. A. dos Santos* M. A. dos Santos* J. Ernsting** J. Ernsting** *Microgravity Laboratory-Brazil / ** King’s College *Microgravity Laboratory-Brazil / ** King’s College London-UK London-UK Intra-ocular and Venous Intra-ocular and Venous Pressures during Head-down Pressures during Head-down Tilt Tilt
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T. Russomano* L. F. B. Chotgues* O. A. Lima de Sá* M. A. dos Santos* J. Ernsting** *Microgravity Laboratory-Brazil / ** King’s College London-UK *Microgravity.
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T. Russomano*T. Russomano*
L. F. B. Chotgues*L. F. B. Chotgues*
O. A. Lima de Sá*O. A. Lima de Sá*
M. A. dos Santos*M. A. dos Santos*
J. Ernsting**J. Ernsting**
*Microgravity Laboratory-Brazil / ** King’s College London-UK*Microgravity Laboratory-Brazil / ** King’s College London-UK
Intra-ocular and Venous Pressures Intra-ocular and Venous Pressures during Head-down Tiltduring Head-down Tilt
ObjectivesObjectives
1) To determine the relationship between IOP 1) To determine the relationship between IOP and forehead venous pressure produced by 15 and forehead venous pressure produced by 15 min exposures to:min exposures to:
0° (supine position), 17° HDT and 34° HDT0° (supine position), 17° HDT and 34° HDT
2) To compare the results obtained with HDT 2) To compare the results obtained with HDT with the ones found in microgravitywith the ones found in microgravity
3) To discuss the physiological mechanisms 3) To discuss the physiological mechanisms involved in the increase of IOP and venous involved in the increase of IOP and venous pressures with HDT and in microgravitypressures with HDT and in microgravity
Physiology of the eye on EarthPhysiology of the eye on Earth
Physiology of the eye on EarthPhysiology of the eye on Earth
Physiology of the eye on EarthPhysiology of the eye on Earth
IOP in MicrogravityIOP in Microgravity
1st German-Russian MIR mission 1992 : 92% IOP rise1st German-Russian MIR mission 1992 : 92% IOP rise
Schwartz R, Draeger J, Groenhoff S, Flade K DSchwartz R, Draeger J, Groenhoff S, Flade K D
IOP increased 58% (19 mmHg) during parabolic flight (20 IOP increased 58% (19 mmHg) during parabolic flight (20 s of µG) compared to baseline values (12 mmHg) (s of µG) compared to baseline values (12 mmHg) (n =11)n =11)
Mader TH et alMader TH et al., Am J Ophtalmol. 1993 Mar 15; 115(3):347-50., Am J Ophtalmol. 1993 Mar 15; 115(3):347-50
Central venous pressure in spaceCentral venous pressure in space Buckey J. C. et al, 1996Buckey J. C. et al, 1996
ConclusionConclusion
• IOP and forehead venous pressures IOP and forehead venous pressures simultaneously increased during simultaneously increased during HDT HDT (r=0.99)(r=0.99) regardless the angle of regardless the angle of tilt employed and both returned to tilt employed and both returned to their control values in the supine their control values in the supine position.position.
Future StudiesFuture Studies
• Measurements of peripheral venous Measurements of peripheral venous pressure of the forehead in pressure of the forehead in microgravity should be made to microgravity should be made to clarify the mechanisms involved in clarify the mechanisms involved in the rise of IOP, which may differ the rise of IOP, which may differ from those found during HDTfrom those found during HDT