IOVS：标准视力测试能预知夜间驾驶能力吗？

已通过机动车辆管理视力测试的司机，并不意味着他或她就能安全驾驶。最近一项研究发现，中等水平视力模糊和白内障的司机夜间识别行人的频率与距离严重下降，即使司机已通过必需的视力测试。

视力模糊和白内障非常普遍，许多有这些情况的人还在继续开车。我们这项研究的目的就是更好地了解这些视力情况如何影响司机在夜间对路旁行人的识别能力和反应能力，同时也想弄清楚，着某一类型服装的行人是否能增强司机夜间的行人识别能力，甚至是司机存在一定程度视力丧失。

研究结果表明，这些视力缺损减少了司机夜间最早识别有行人存在的距离。具正常视力的司机会在更远的距离内识别行人，平均来说，此识别距离比视力模糊司机的远3.6倍，比白内障司机的远5.5倍。

这就暗示，为了最大化司机从安全距离看见行人的能力，他们应该戴上最佳光学矫正镜片和尽早进行白内障手术，以避免潜在的危险驾驶情况。

深入研究应该进一步探讨矫正屈光不正、白内障和其他形式视觉缺损对驾驶性能和安全性的影响，以及确定一些测量视觉能力较新方法的价值，其中视觉能力包括散光测试和对比敏感性。只测量视力不能提供我们最好方式来确定谁是安全驾驶。（生物谷bioon.com）

doi:10.1167/iovs.11-9083
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Even moderate visual impairments degrade drivers' ability to see pedestrians at night

J. M. Wood, R. Tyrrell, A. Chaparro, R. Marszalek, T. Carberry, B. S. Chu

Purpose: To determine the effect of moderate levels of refractive blur and simulated cataracts on nighttime pedestrian conspicuity in the presence and absence of headlamp glare. Methods: The ability to recognize pedestrians at night was measured in 28 young adults (M=27.6 years) under three visual conditions: normal vision, refractive blur and simulated cataracts; mean acuity was 20/40 or better in all conditions. Pedestrian recognition distances were recorded while participants drove an instrumented vehicle along a closed road course at night. Pedestrians wore one of three clothing conditions and oncoming headlamps were present for 16 participants and absent for 12 participants. Results: Simulatedvisual impairment and glare significantly reduced the frequency with which drivers recognized pedestrians and the distance at which the drivers first recognized them. Simulated cataracts were significantly more disruptive than blur even though photopic visual acuity levels were matched. With normal vision, drivers responded to pedestrians at 3.6x and 5.5x longer distances on average than for the blur or cataract conditions, respectively. Even in the presence ofvisual impairment and glare, pedestrians were recognized more often and at longer distances when they wore a "biological motion" reflective clothing configuration than when they wore a reflective vest or black clothing. Conclusions: Drivers' ability to recognize pedestrians at night is degraded by common visual impairments even when the drivers' mean visual acuity meets licensing requirements. To maximize drivers' ability to see pedestrians, drivers should wear their optimum optical correction, and cataract surgery should be performed early enough to avoid potentially dangerous reductions in visualperformance.