Influence of the Water-Drinking Test on Intraocular Pressure, Schlemm's Canal, and Autonomic Nervous System Activity

et al. 2020

BMC Ophthalmol

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Background: The Valsalva maneuver (VM) is widely used in daily life, and has been reported to cause high intraocular pressure (IOP). This study aimed to assess changes in IOP, the Schlemm's canal (SC), autonomic nervous system activity, and iridocorneal angle morphology in healthy individuals during different phases of the VM. Methods: The high frequency (HF) of heart rate (HR) variability, the ratio of low frequency power (LF) and HF (LF/HF), heart rate (HR), IOP, systolic (SBP) and diastolic blood pressure (DBP), the area of SC (SCAR), pupil diameter (PD), and some iridocorneal angle parameters (AOD500, ARA750, TIA500 and TISA500) were measured in 29 young healthy individuals at baseline, phase 2, and phase 4 of the VM. SBP and DBP were measured to calculate mean arterial pressure (MAP) and mean ocular perfusion pressure (MOPP). HF and the LF/HF ratio were recorded using Kubios HR variability premium software to evaluate autonomic nervous system activity. The profiles of the anterior chamber were captured by a Spectralis optical coherence tomography device (anterior segment module). Results: Compared with baseline values, in phase 2 of the VM, HR, LF/HF, IOP (15.1 ± 2.7 vs. 18.8 ± 3.5 mmHg, P < 0.001), SCAR (mean) (7712.112 ± 2992.14 vs. 8921.12 ± 4482.79 μm 2 , P = 0.039), and PD increased significantly, whereas MOPP, AOD500, TIA500, and TISA500 decreased significantly. In phase 4, DBP, MAP, AOD500, ARA750, TIA500and TISA500 were significantly lower than baseline value, while PD and HF were remarkably larger than baseline. The comparison between phase 2 and phase 4 showed that HR, IOP (18.8 ± 3.5 vs. 14.7 ± 2.9 mmHg, P < 0.001) and PD decreased significantly from phase 2 to phase 4, but there were no significant differences in other parameters. Conclusions: The expansion and collapse of the SC in different phases of the VM may arise from changes in autonomic nervous system activity. Further, the effects of the VM on IOP may be attributed to changes in blood flow and ocular anatomy. Trial registration: This observational study was approved by the ethics committee of Tongji Hospital (Registration Number: ChiCTR-OON-16007850, Date: 01.28.2016).

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 97%

Dual effect of the Valsalva maneuver on autonomic nervous system activity, intraocular pressure, Schlemm’s canal, and iridocorneal angle morphology

et al. 2020

BMC Ophthalmol

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“…The VM, is widely used to examine autonomic nervous system function, and is divided into 4 physiological phases [3,7] a lower LF is generally considered to be the combined sympathetic and parasympathetic influence, although this remains controversial [14,15]. An increasing LF/HF represents a predominant sympathetic activation [19].…”

Section: Discussionmentioning

confidence: 99%

“…By contrast, Stuart et al found no association of IOP changes with the electromyographic increase during the VM, but rather an influence of the autonomic nervous system [5]. We previously reported that a decrease in IOP was associated with sympathetic nerve stimulation during aerobic exercise [14], while parasympathetic stimulation caused by the water-drinking test may cause collapse of Schlemm's canal (SC) and an increase in IOP [15].…”

Section: Introductionmentioning

confidence: 97%

Dual effect of the Valsalva maneuver on autonomic nervous system activity, intraocular pressure, Schlemm’s canal, and iridocorneal angle morphology

et al. 2019

Preprint

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Background: The Valsalva maneuver (VM) is widely used in daily life, and has been reported to cause high intraocular pressure (IOP). This study aimed to assess changes in IOP, the Schlemm’s canal (SC), autonomic nervous system activity, and iridocorneal angle morphology in healthy individuals during different phases of the VM. Methods: The high frequency (HF) of heart rate (HR) variability, the ratio of low frequency power (LF) and HF (LF/HF), heart rate (HR), IOP, systolic (SBP) and diastolic blood pressure (DBP), the area of SC (SCAR), pupil diameter (PD), and some iridocorneal angle parameters (AOD500, ARA750, TIA500 and TISA500) were measured in 29 young healthy individuals at baseline, phase 2, and phase 4 of the VM. SBP and DBP were measured to calculate mean arterial pressure (MAP) and mean ocular perfusion pressure (MOPP). HF and the LF/HF ratio were recorded using Kubios HR variability premium software to evaluate autonomic nervous system activity. The profiles of the anterior chamber were captured by a Spectralis optical coherence tomography device (anterior segment module). Results: Compared with baseline values, in phase 2 of the VM, HR, LF/HF, IOP (15.1±2.7 vs. 18.8±3.5 mmHg, P < 0.001), SCAR(mean) (7712.112±2992.14 vs. 8921.12±4482.79 μm2, P = 0.039), and PD increased significantly, whereas MOPP, AOD500, TIA500, and TISA500 decreased significantly. In phase 4, DBP, MAP, AOD500, ARA750, TIA500and TISA500 were significantly lower than baseline value, while PD and HF were remarkably larger than baseline. The comparison between phase 2 and phase 4 showed that HR, IOP (18.8±3.5 vs. 14.7±2.9 mmHg, P < 0.001) and PD decreased significantly from phase 2 to phase 4, but there were no significant differences in other parameters. Conclusions: The expansion and collapse of the SC in different phases of the VM may arise from changes in autonomic nervous system activity. Further, the effects of the VM on IOP may be attributed to changes in blood flow and ocular anatomy.

“…The VM is common in the daily life [1,7] and high IOP is a major risk factor for glaucoma disease [12]. We have previously shown that an IOP decrease was associated with sympathetic nerve stimulation which is caused by aerobic exercise [13] and parasympathetic nervous system stimulation caused by water-drinking test may lead to the collapse of Schlemm's canal (SC) and an IOP increase [14]. In this study, we therefore research on the possible mechanism of the IOP fluctuations in different phases of the VM.…”

Section: Introductionmentioning

confidence: 99%

Dual effect of the Valsalva maneuver on autonomic nervous system activity, intraocular pressure, Schlemm’s canal, and iridocorneal angle morphology

et al. 2019

Preprint

Self Cite

Background The Valsalva maneuver (VM) is common in the daily life and has been reported to cause high intraocular pressure (IOP). This study aimed to assess changes in IOP, Schlemm’s canal (SC), autonomic nervous system activity and iridocorneal angle morphology in healthy individuals during different phases of the VM. Methods The high frequency (HF) of heart rate variability (HRV), the ratio of low frequency power and high frequency power (LF/HF), heart rate (HR), IOP, systolic (SBP) and diastolic blood pressure (DBP), the area of Schlemm’s canal (SCAR), pupil diameter (PD) and some iridocorneal angle parameters (AOD500, ARA750, TIA500 and TISA500) were measured in 29 young healthy individuals at baseline, phase 2 and phase 4 of the VM. SBP and DBP were measured to calculate mean arterial pressure (MAP) and mean ocular perfusion pressure (MOPP). HF and LF/HF ratio were recorded using Kubios HRV Premium software to evaluate autonomic nervous activity. The profiles of anterior chamber were captured by a Spectralis optical coherence tomography device (anterior segment module). Results Compared with baseline values, in phase 2 of the VM, HR, LF/HF, IOP (15.1 ± 2.7 vs. 18.8 ± 3.5 mmHg, p < 0.001), SCAR(mean) (7448.64 ± 3230.82 vs. 8851.43 ± 4231.15 μm2, p = 0.038) and PD increased significantly, whereas MOPP, AOD500, ARA750, TIA500 and TISA500 decreased significantly. In phase 4, HR, DBP, MAP, MOPP, AOD500, ARA750, TIA500and TISA500 were significantly lower than baseline value, while PD and HF were remarkably larger than baseline. The comparison between phase 2 and phase 4 showed that HR, IOP (19.1 ± 3.3 vs. 14.7 ± 2.9 mmHg, p < 0.001) and PD decreased significantly from phase 2 to phase 4, but there were no significant differences in other parameters. Conclusions The expansion and collapse of SC in different phases of the VM may be arise from the changes of autonomic nervous system activity, while its influence on IOP could be counteracted even reversed by the changes of blood flow and ocular anatomy.