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. TRIAL REGISTRATION This observational study was approved by the ethics committee of Tongji Hospital (Registration Number: ChiCTR-OON-16007850, Date: 01.28.2016).

中文翻译：

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Valsalva动作对自主神经系统活动，眼内压，Schlemm根管和虹膜角膜角度形态的双重影响。

背景技术Valsalva操作（VM）在日常生活中被广泛使用，并且据报道会引起高眼内压（IOP）。这项研究旨在评估健康个体在VM不同阶段的IOP，Schlemm运河（SC），自主神经系统活动和虹膜角膜角形态的变化。方法：心率（HR）变异的高频（HF），低频功率（LF）与HF的比率（LF / HF），心率（HR），IOP，收缩压（SBP）和舒张压（DBP） ），在VM的基线，第2阶段和第4阶段对29位年轻健康个体进行了SC面积（SCAR），瞳孔直径（PD）和一些虹膜角膜角参数（AOD500，ARA750，TIA500和TISA500）的测量。测量SBP和DBP以计算平均动脉压（MAP）和平均眼灌注压（MOPP）。使用Kubios HR variability premium软件记录HF和LF / HF比率，以评估自主神经系统活动。前房的轮廓由Spectralis光学相干断层扫描设备（前节模块）捕获。结果与基线值相比，在VM的第二阶段中，HR，LF / HF，IOP（15.1±2.7与18.8±3.5 mmHg，P <0.001），SCAR（平均值）（7712.112±2992.14与8921.12±4482.79μm2 ，P = 0.039），PD显着增加，而MOPP，AOD500，TIA500和TISA500显着降低。在第4阶段，DBP，MAP，AOD500，ARA750，TIA500和TISA500显着低于基线值，而PD和HF显着高于基线。第2阶段和第4阶段之间的比较显示HR，IOP（18.8±3.5 vs. 14.7±2.9 mmHg，P <0。001）和PD从第2阶段到第4阶段显着降低，但其他参数没有显着差异。结论在VM的不同阶段，SC的扩张和萎缩可能是由于自主神经系统活动的改变引起的。此外，VM对IOP的影响可能归因于血流和眼部解剖结构的变化。试验注册本观察性研究获得同济医院伦理委员会的批准（注册号：ChiCTR-OON-16007850，日期：2016年1月28日）。