摘要
黄斑变性是眼科常见可引起严重视功能损害的疾病。以往临床上评价眼形觉功能改变通常是用视力表进行测量。视力表是在白色的背景下由黑色符号或视标所制成,它表明的视力是对微小细节(高空间频率)的分辩能力,是最大的对比,亦是100%的对比。因此,视力测量反映的仅仅是黄斑部对高对比,小目标的分辨功能。然而,感知是十分复杂的,它依赖于适应、对比辨别、运动敏感性和颜色敏感度。人们在日常生活中、周围环境中的目标几乎不存在100%的对比,在多云天空中的灰色飞机的对比度仅是2%或更低。Campbell 等首先使用不同空间频率的正弦波光栅,检测了人视觉系统的对比敏感度函数(Contrast Sensitivity Func—
The authors adopted the VCTS 6500 CSF Test Cards (USA) in theexamination of CSF of the blind and the low visioned due to maculardegeneration before and after the use of visual aids.It was found thatthe improvement in visual acuity was accompanied by improvement inCSF and elevation of the peak value.However,the improvement in CSFmight not parallel the improvement of visual acuity in both eyes:some-times,the eye of lower visual acuity could have a higher CSF improve-meat than the eye of better visual acuity.Therefore,the CSF test canbe useful in guiding the selection of optical visual aids.
