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.
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机译:背景:视网膜灌注变异性会影响眼部疾病和生理学目的:评估20名健康志愿者的视网膜中央动脉(CRA)血流对体温变化的反应设置和设计:非干预实验人体研究材料和方法:基线记录的数据:使用彩色多普勒仪的眼表温度(OST),以°C(热度计)为单位,CRA收缩期峰值速度(PSV),舒张末期速度(EDV),单位为cm / s。随机分配眼的侧面和温度变化(电灯加热/冰凝胶冷却)。记录的主要结果是:升温或降温后立即和十分钟后的OST和眼内压(IOP)。统计分析:重复测量方差分析。结果:(n = 20;μ±SD):预热值为:CRA-PSV和EDV在三,六和九分钟的升温或降温。 OST:34.5±1.02°C,CRA-PSV:9.3±2.33 cm / s,CRA-EDV:4.6±1.27 cm / s。升温后,OST显着提高了1.96°C(95%CI:1.54至2.37),但十分钟后又恢复到基线。仅在三分钟时,PSV显着提高了1.21 cm / s(95%CI:0.51至1.91)。预冷值为:OST:34.5±0.96°C,CRA-PSV:9.7±2.45 cm / s,CRA-EDV:4.7±1.12 cm / s。冷却后,OST显着降低了2.81°C(95%CI:2.30至3.33),并在十分钟后恢复到基线。在三分钟时,CRA-PSV显着下降了1.10cm / s(95%CI:?2.05至?0.15),而CRA-EDV下降了0.81(95%CI:?1.47至?0.14)。在六分钟时,PSV(95%CI:?1.38至?0.03)和EDV(95%CI:?1.26至?0.02)均显着降低。十分钟时的所有值均与基线相当。 IOP在变暖时无明显变化(相差95%CI:约0.17至1.57mmHg),但降温后显着降低(95%CI:约2.95至4.30mmHg)。十分钟后,IOP恢复到基线。结论:这项研究证实了CRA流量在变暖时显着增加,而在冷却时则下降,尽管IOP显着降低。
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