TY - JOUR
T1 - Effect of body position on epsicleral venous pressure in healthy subjects
AU - Arora, Nitika
AU - McLaren, Jay W.
AU - Hodge, David O.
AU - Sit, Arthur J.
N1 - Funding Information:
Supported by the Bright Focus Foundation, Mayo Foundation for Medical Education and Research, and an unrestricted departmental grant from Research to Prevent Blindness. Disclosure: N. Arora, None; J.W. McLaren, None; D.O. Hodge, None; A.J. Sit, None
Publisher Copyright:
© 2017 The Authors.
PY - 2017/10
Y1 - 2017/10
N2 - PURPOSE. The mechanism of IOP change during a body position change is poorly understood. In this study, we investigated changes in episcleral venous pressure (EVP) between two body positions, sitting and inclined, and compared this with changes in IOP. METHODS. This study was a prospective, comparative case series of 43 eyes of 24 healthy volunteers. IOP was measured using a pneumatonometer in the seated position. EVP was then measured in a selected episcleral vein by using an automated, slit-lamp–mounted venomanometer. Thirty minutes later, the subject was placed in an inclined position with the neck extended and the head resting on the chin rest of the slit lamp. After 5 minutes, IOP and EVP in the same vein were remeasured. EVP in the inclined position was compared with EVP in the seated position, and the change in IOP was compared with the change in EVP. Statistical significance was determined using generalized estimating equation models. RESULTS. Mean IOP increased from 11.4 ± 3.0 mm Hg (mean ± SD) in the sitting position to 13.1 ± 3.4 mm Hg in the inclined position (P < 0.001). Mean EVP increased from 6.4 ± 1.4 mm Hg in the sitting position to 7.8 ± 1.7 mm Hg in the inclined position (P < 0.001). The postural rise in IOP was not different from the rise in EVP (P = 0.18). CONCLUSIONS. In the inclined position, IOP and EVP are higher than they are in the sitting position. The posture-induced rise in IOP can be attributed to an increase in EVP.
AB - PURPOSE. The mechanism of IOP change during a body position change is poorly understood. In this study, we investigated changes in episcleral venous pressure (EVP) between two body positions, sitting and inclined, and compared this with changes in IOP. METHODS. This study was a prospective, comparative case series of 43 eyes of 24 healthy volunteers. IOP was measured using a pneumatonometer in the seated position. EVP was then measured in a selected episcleral vein by using an automated, slit-lamp–mounted venomanometer. Thirty minutes later, the subject was placed in an inclined position with the neck extended and the head resting on the chin rest of the slit lamp. After 5 minutes, IOP and EVP in the same vein were remeasured. EVP in the inclined position was compared with EVP in the seated position, and the change in IOP was compared with the change in EVP. Statistical significance was determined using generalized estimating equation models. RESULTS. Mean IOP increased from 11.4 ± 3.0 mm Hg (mean ± SD) in the sitting position to 13.1 ± 3.4 mm Hg in the inclined position (P < 0.001). Mean EVP increased from 6.4 ± 1.4 mm Hg in the sitting position to 7.8 ± 1.7 mm Hg in the inclined position (P < 0.001). The postural rise in IOP was not different from the rise in EVP (P = 0.18). CONCLUSIONS. In the inclined position, IOP and EVP are higher than they are in the sitting position. The posture-induced rise in IOP can be attributed to an increase in EVP.
KW - Episcleral venous pressure
KW - Intraocular pressure
KW - Prone position
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U2 - 10.1167/iovs.17-22154
DO - 10.1167/iovs.17-22154
M3 - Article
C2 - 28986593
AN - SCOPUS:85031727794
SN - 0146-0404
VL - 58
SP - 5151
EP - 5156
JO - Investigative Ophthalmology and Visual Science
JF - Investigative Ophthalmology and Visual Science
IS - 12
ER -