Regulation of choroidal blood flow during isometric exercise at different levels of intraocular pressure

Purpose: There is evidence that choroidal blood flow (ChBF) is regulated in a complex way during changes in ocular perfusion pressure (OPP). We hypothesized that ChBF regulates better in response to changes in mean arterial pressure (MAP) than in intraocular pressure (IOP). Methods: Eighteen volunte...

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Main Authors: Popa-Cherecheanu, Alina, Schmidl, Doreen, Werkmeister, René M., Chua, Jacqueline, Garhöfer, Gerhard, Schmetterer, Leopold
Other Authors: Lee Kong Chian School of Medicine (LKCMedicine)
Format: Article
Language:English
Published: 2019
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Online Access:https://hdl.handle.net/10356/88859
http://hdl.handle.net/10220/47636
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spelling sg-ntu-dr.10356-888592020-11-01T05:25:50Z Regulation of choroidal blood flow during isometric exercise at different levels of intraocular pressure Popa-Cherecheanu, Alina Schmidl, Doreen Werkmeister, René M. Chua, Jacqueline Garhöfer, Gerhard Schmetterer, Leopold Lee Kong Chian School of Medicine (LKCMedicine) DRNTU::Science::Medicine Ocular Perfusion Pressure Choroidal Blood Flow Purpose: There is evidence that choroidal blood flow (ChBF) is regulated in a complex way during changes in ocular perfusion pressure (OPP). We hypothesized that ChBF regulates better in response to changes in mean arterial pressure (MAP) than in intraocular pressure (IOP). Methods: Eighteen volunteers (mean age, 26 years) were recruited for a randomized, three-way crossover design. MAP was varied via isometric exercise. IOP was either kept normal or elevated by 10 or 20 mm Hg by using a suction cup. Subfoveal ChBF was measured continuously for 8 minutes with laser Doppler flowmetry and OPP was calculated as 2/3*MAP-IOP. For data analysis, values from all subjects were pooled according to either IOP or MAP values, and correlation analyses were done. Results: When data were grouped according to IOP, no correlation was observed between ChBF and MAP, but ChBF was lower the higher the IOP (P < 0.001). When data were grouped according to MAP, a significant correlation was found between ChBF and IOP (P < 0.001). When data were pooled according to IOP, the correlation between ChBF and OPP was weaker (P < 0.05). The OPP at which ChBF significantly increased from baseline was 61.3% ± 4.9% without suction cup, 65.2% ± 3.5% when IOP was increased by 10 mm Hg, and slightly lower when IOP was increased by 20 mm Hg (56.3% ± 4.8%, P = 0.07), but this effect did not reach the level of significance. Conclusions: The present study provides further evidence that the regulation of ChBF during changes in OPP is controlled by complex mechanisms in humans and has less capacity to adapt to IOP elevation than to MAP increase. Published version 2019-02-11T08:33:23Z 2019-12-06T17:12:33Z 2019-02-11T08:33:23Z 2019-12-06T17:12:33Z 2019 Journal Article Popa-Cherecheanu, A., Schmidl, D., Werkmeister, R. M., Chua, J., Garhöfer, G., & Schmetterer, L. (2019). Regulation of Choroidal Blood Flow During Isometric Exercise at Different Levels of Intraocular Pressure. Investigative Opthalmology & Visual Science, 60(1), 176-. doi:10.1167/iovs.18-24992 0146-0404 https://hdl.handle.net/10356/88859 http://hdl.handle.net/10220/47636 10.1167/iovs.18-24992 en Investigative Opthalmology & Visual Science © 2019 The Authors. This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License. 7 p. application/pdf
institution Nanyang Technological University
building NTU Library
continent Asia
country Singapore
Singapore
content_provider NTU Library
collection DR-NTU
language English
topic DRNTU::Science::Medicine
Ocular Perfusion Pressure
Choroidal Blood Flow
spellingShingle DRNTU::Science::Medicine
Ocular Perfusion Pressure
Choroidal Blood Flow
Popa-Cherecheanu, Alina
Schmidl, Doreen
Werkmeister, René M.
Chua, Jacqueline
Garhöfer, Gerhard
Schmetterer, Leopold
Regulation of choroidal blood flow during isometric exercise at different levels of intraocular pressure
description Purpose: There is evidence that choroidal blood flow (ChBF) is regulated in a complex way during changes in ocular perfusion pressure (OPP). We hypothesized that ChBF regulates better in response to changes in mean arterial pressure (MAP) than in intraocular pressure (IOP). Methods: Eighteen volunteers (mean age, 26 years) were recruited for a randomized, three-way crossover design. MAP was varied via isometric exercise. IOP was either kept normal or elevated by 10 or 20 mm Hg by using a suction cup. Subfoveal ChBF was measured continuously for 8 minutes with laser Doppler flowmetry and OPP was calculated as 2/3*MAP-IOP. For data analysis, values from all subjects were pooled according to either IOP or MAP values, and correlation analyses were done. Results: When data were grouped according to IOP, no correlation was observed between ChBF and MAP, but ChBF was lower the higher the IOP (P < 0.001). When data were grouped according to MAP, a significant correlation was found between ChBF and IOP (P < 0.001). When data were pooled according to IOP, the correlation between ChBF and OPP was weaker (P < 0.05). The OPP at which ChBF significantly increased from baseline was 61.3% ± 4.9% without suction cup, 65.2% ± 3.5% when IOP was increased by 10 mm Hg, and slightly lower when IOP was increased by 20 mm Hg (56.3% ± 4.8%, P = 0.07), but this effect did not reach the level of significance. Conclusions: The present study provides further evidence that the regulation of ChBF during changes in OPP is controlled by complex mechanisms in humans and has less capacity to adapt to IOP elevation than to MAP increase.
author2 Lee Kong Chian School of Medicine (LKCMedicine)
author_facet Lee Kong Chian School of Medicine (LKCMedicine)
Popa-Cherecheanu, Alina
Schmidl, Doreen
Werkmeister, René M.
Chua, Jacqueline
Garhöfer, Gerhard
Schmetterer, Leopold
format Article
author Popa-Cherecheanu, Alina
Schmidl, Doreen
Werkmeister, René M.
Chua, Jacqueline
Garhöfer, Gerhard
Schmetterer, Leopold
author_sort Popa-Cherecheanu, Alina
title Regulation of choroidal blood flow during isometric exercise at different levels of intraocular pressure
title_short Regulation of choroidal blood flow during isometric exercise at different levels of intraocular pressure
title_full Regulation of choroidal blood flow during isometric exercise at different levels of intraocular pressure
title_fullStr Regulation of choroidal blood flow during isometric exercise at different levels of intraocular pressure
title_full_unstemmed Regulation of choroidal blood flow during isometric exercise at different levels of intraocular pressure
title_sort regulation of choroidal blood flow during isometric exercise at different levels of intraocular pressure
publishDate 2019
url https://hdl.handle.net/10356/88859
http://hdl.handle.net/10220/47636
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