急性轻、中度缺氧对视觉对比敏感度函数(CSF)的影响

Effects of Acute Light and Moderate Hypoxia on Vision Contrast Sensitivity Function (CSF)

15名青年男性受试者,在暗室静卧位,吸含氧量分别为17.8％、13.5—14.0％和12.0％的氮氧混合气。分别在实验前,中和后,用0.5、1.1、1.8、3.7、9.2和29.1周/度六个空间频率,测试了视觉对比敏感度。结果表明,在上述3种缺氧条件下,所有空间频率的对比敏感度均明显下降。但各频率间的对比敏感度变化不一致。中频(1.8、3.7和9.2周/度)的对比敏感度在全部3种缺氧条件下均显著下降(P<0.01),而低频(0.5和1.1周/度)分别在17.8％和13.5-14.0％氧含量时下降明显(P<0.05),和高频(29.1周/度)仅在12.0％氧含量时才显著降低(P<0.05)。上述结果说明,急性轻度缺氧主要对低,中频空间频率的对比敏感度产生影响。因此,CSF可作为轻度缺氧时视觉和脑功效的评价指标。

In the dark room, 15 young male subjects with supine position were tested by breathing 3 different oxygen-nitrogen mixtures containing 17.8%, 13.5-14.0%and 12.0% of oxygen respectively.Vision contrast sensitivity function was measured before, during and after the breathing of the Q_2-N_2 mixtures by using 6 spatial frequencies, that is, 0.5, 1.1,1.8, 3.7, 9.2, and 29.1 cydes/deg.Results showed that CSF measured at the 6 frequencies declined significantly under hypoxic conditions.However, the rate of the decline was various at different spatial frequencis.CSF declined significantly(P<0.01) at medium frequendes(1.8, 3.7 and 92 cydes/deg) under all 3 hypoxic conditions, and the decline of CSF was also significant(P<0.05) at low frequencies (0.5 and 1.1 cydes/deg) with O_2 Concentration of 17.8% and 13.5-14.0%, while that of CSF at high frequency (29.1cydes/deg) was significant(P<0.05) only at 12.0% O_2 concentration.The results indicated that the response of CSF to mild or moderate hypoxia is more sensitive than other indexes of visual function.