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Changes in central retinal artery blood flow after ocular warming and cooling in healthy subjects
CONTEXT: Retinal perfusion variability impacts ocular disease and physiology. AIM: To evaluate the response of central retinal artery (CRA) blood flow to temperature alterations in 20 healthy volunteers. SETTING AND DESIGN: Non-interventional experimental human study. MATERIALS AND METHODS: Baseline...
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Formato: | Texto |
Lenguaje: | English |
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Medknow Publications
2010
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Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2886247/ https://www.ncbi.nlm.nih.gov/pubmed/20413919 http://dx.doi.org/10.4103/0301-4738.62641 |
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author | Shamshad, M A Amitava, A K Ahmad, I Wahab, S |
author_facet | Shamshad, M A Amitava, A K Ahmad, I Wahab, S |
author_sort | Shamshad, M A |
collection | PubMed |
description | CONTEXT: Retinal perfusion variability impacts ocular disease and physiology. AIM: To evaluate the response of central retinal artery (CRA) blood flow to temperature alterations in 20 healthy volunteers. SETTING AND DESIGN: Non-interventional experimental human study. MATERIALS AND METHODS: Baseline data recorded: Ocular surface temperature (OST) in °C (thermo-anemometer), CRA peak systolic velocity (PSV) and end diastolic velocity (EDV) in cm/s using Color Doppler. Ocular laterality and temperature alteration (warming by electric lamp/cooling by ice-gel pack) were randomly assigned. Primary outcomes recorded were: OST and intraocular pressure (IOP) immediately after warming or cooling and ten minutes later; CRA-PSV and EDV at three, six and nine minutes warming or cooling. STATISTICAL ANALYSIS: Repeated measures ANOVA. RESULTS: (n = 20; μ ± SD): Pre-warming values were; OST: 34.5 ± 1.02°C, CRA-PSV: 9.3 ± 2.33 cm/s, CRA-EDV: 4.6 ± 1.27 cm/s. OST significantly increased by 1.96°C (95% CI: 1.54 to 2.37) after warming, but returned to baseline ten minutes later. Only at three minutes, the PSV significantly rose by 1.21 cm/s (95% CI: 0.51to1.91). Pre-cooling values were: OST: 34.5 ± 0.96°C, CRA-PSV: 9.7 ± 2.45 cm/s, CRA-EDV: 4.7 ± 1.12 cm/s. OST significantly decreased by 2.81°C (95% CI: −2.30 to −3.37) after cooling, and returned to baseline at ten minutes. There was a significant drop in CRA-PSV by 1.10cm/s (95% CI: −2.05 to −0.15) and CRA-EDV by 0.81 (95% CI: −1.47 to −0.14) at three minutes. At six minutes both PSV (95% CI: −1.38 to −0.03) and EDV (95% CI: −1.26 to −0.02) were significantly lower. All values at ten minutes were comparable to baseline. The IOP showed insignificant alteration on warming (95% CI of difference: −0.17 to 1.57mmHg), but was significantly lower after cooling (95% CI: −2.95 to −4.30mmHg). After ten minutes, IOP had returned to baseline. CONCLUSION: This study confirms that CRA flow significantly increases on warming and decreases on cooling, the latter despite a significant lowering of IOP. |
format | Text |
id | pubmed-2886247 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2010 |
publisher | Medknow Publications |
record_format | MEDLINE/PubMed |
spelling | pubmed-28862472010-07-02 Changes in central retinal artery blood flow after ocular warming and cooling in healthy subjects Shamshad, M A Amitava, A K Ahmad, I Wahab, S Indian J Ophthalmol Original Article CONTEXT: Retinal perfusion variability impacts ocular disease and physiology. AIM: To evaluate the response of central retinal artery (CRA) blood flow to temperature alterations in 20 healthy volunteers. SETTING AND DESIGN: Non-interventional experimental human study. MATERIALS AND METHODS: Baseline data recorded: Ocular surface temperature (OST) in °C (thermo-anemometer), CRA peak systolic velocity (PSV) and end diastolic velocity (EDV) in cm/s using Color Doppler. Ocular laterality and temperature alteration (warming by electric lamp/cooling by ice-gel pack) were randomly assigned. Primary outcomes recorded were: OST and intraocular pressure (IOP) immediately after warming or cooling and ten minutes later; CRA-PSV and EDV at three, six and nine minutes warming or cooling. STATISTICAL ANALYSIS: Repeated measures ANOVA. RESULTS: (n = 20; μ ± SD): Pre-warming values were; OST: 34.5 ± 1.02°C, CRA-PSV: 9.3 ± 2.33 cm/s, CRA-EDV: 4.6 ± 1.27 cm/s. OST significantly increased by 1.96°C (95% CI: 1.54 to 2.37) after warming, but returned to baseline ten minutes later. Only at three minutes, the PSV significantly rose by 1.21 cm/s (95% CI: 0.51to1.91). Pre-cooling values were: OST: 34.5 ± 0.96°C, CRA-PSV: 9.7 ± 2.45 cm/s, CRA-EDV: 4.7 ± 1.12 cm/s. OST significantly decreased by 2.81°C (95% CI: −2.30 to −3.37) after cooling, and returned to baseline at ten minutes. There was a significant drop in CRA-PSV by 1.10cm/s (95% CI: −2.05 to −0.15) and CRA-EDV by 0.81 (95% CI: −1.47 to −0.14) at three minutes. At six minutes both PSV (95% CI: −1.38 to −0.03) and EDV (95% CI: −1.26 to −0.02) were significantly lower. All values at ten minutes were comparable to baseline. The IOP showed insignificant alteration on warming (95% CI of difference: −0.17 to 1.57mmHg), but was significantly lower after cooling (95% CI: −2.95 to −4.30mmHg). After ten minutes, IOP had returned to baseline. CONCLUSION: This study confirms that CRA flow significantly increases on warming and decreases on cooling, the latter despite a significant lowering of IOP. Medknow Publications 2010 /pmc/articles/PMC2886247/ /pubmed/20413919 http://dx.doi.org/10.4103/0301-4738.62641 Text en © Indian Journal of Ophthalmology http://creativecommons.org/licenses/by/2.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. |
spellingShingle | Original Article Shamshad, M A Amitava, A K Ahmad, I Wahab, S Changes in central retinal artery blood flow after ocular warming and cooling in healthy subjects |
title | Changes in central retinal artery blood flow after ocular warming and cooling in healthy subjects |
title_full | Changes in central retinal artery blood flow after ocular warming and cooling in healthy subjects |
title_fullStr | Changes in central retinal artery blood flow after ocular warming and cooling in healthy subjects |
title_full_unstemmed | Changes in central retinal artery blood flow after ocular warming and cooling in healthy subjects |
title_short | Changes in central retinal artery blood flow after ocular warming and cooling in healthy subjects |
title_sort | changes in central retinal artery blood flow after ocular warming and cooling in healthy subjects |
topic | Original Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2886247/ https://www.ncbi.nlm.nih.gov/pubmed/20413919 http://dx.doi.org/10.4103/0301-4738.62641 |
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