轻度急性缺氧对飞行人员对比视力的影响及其相关因素分析

目的：探讨轻度急性缺氧对视觉系统识别目标背景对比能力的影响程度及其生理机制。方法：用投射式双变量对比视力表在90Lx照度下检查31名中国海军航空兵飞行人员呼吸空气和呼吸低氧时13个不同对比度的视力，同步监测心率，血氧饱和度。结果：31名飞行员低氧对比视力综合13个对比度平均下降率为10．8％，低氧时，高，中，低对比度时的对比视力平均下降率与缺氧后心率变化率，血氧饱和度平均值显著相关（P＜0．05）。结论：轻度急性缺氧对视觉系统识别目标背景对比能力有显著影响，轻度急性缺氧对低对比视力影响最为显著，机体对缺氧敏感度越高，对比视力下降越明显。

The Effect of Acute Low-grade Hypoxia on the Contrast Visual Acuity of Pilots and an Analysis of Correlative Factors

Objective: To investigate the effect of acute hypoxia on pilots' ability of distinguishing targets from backgrounds, and to discuss the physiological mechanism. Methods: Using a contrast vision chart illuminated at 90 Lx, contrast visual acuity (CVA) at 13 contrast levels was measured in 31 pilots with normal visual acuity in normal and in low oxygen. Heart rate and oxygen saturation of blood were also examined at the same time. Results: The average CVA in low oxygen decreased by 10.8%, compared with the average CVA in normal oxygen. The CVA at low, middle and high contrast levels decreased by 10.9%, 9.7% and 14.2% respectively . The decrease of CVA in low oxygen significantly correlated with heart rate and oxygen saturation of blood (P<0.05). Conclusion: The effect of acute hypoxia on pilots' ability of distinguishing targets from backgrounds is notable. The more sensitive the body to acuity hypoxia was, the lower the CVA in low oxygen was.