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目的 研究时间频率和空间频率对扫描图像翻转诱发电位视力准确度的影响。方法 比较 10例 2 0眼正常志愿者SPVER视力和对数视力表视力。在SPVER视力的测定中用 7个不同空间频率的光栅条纹连续扫描 ,所得的数据经离散傅立叶分析后 ,获得振幅 -空间频率曲线 ,并通过外推法估计其视力。诱发电位测定的时间频率分别为 8、 12、 16、 2 0、 2 4Hz ,根据测试距离来调整空间频率。结果 与视力表视力比较各时间频率测定的SPVER视力有良好的相关r =0 87～ 0 5 ,各空间频率间测定的视力有良好的相关性r=0 72～ 0 96。三种不同空间频率测试的SPVER视力和视力表视力比较在低视力段无差异在高视力段所设空间频率越高结果越接近视力表视力。结论 SPVEP视力与视力表视力有良好的相关性。但为使测定的结果更准确可根据条件选取相应的时间和空间频率。
Objective To study the effect of time frequency and spatial frequency on visual acuity accuracy of scan evoked potentials. Methods The SPVER visual acuity and logarithmic visual acuity of 10 normal volunteers were compared. In the determination of SPVER vision with seven different spatial frequency grating stripes continuous scanning, the data obtained by the discrete Fourier analysis, the amplitude-space frequency curve obtained, and estimated by extrapolation of vision. The time frequency of the evoked potentials were 8, 12, 16, 20, 24Hz respectively, and the spatial frequency was adjusted according to the test distance. Results and vision chart visual acuity SPVER visual acuity measured at each time frequency has a good correlation r = 0 87 ~ 0 5, visual acuity measured between spatial frequencies have a good correlation r = 0 72 ~ 0 96. Three different spatial frequency test SPVER vision and visual acuity chart visual acuity no difference in the low-vision segment set in the high-vision segment set the higher the spatial frequency of the results closer to the visual acuity. Conclusion SPVEP visual acuity and visual acuity have a good correlation. However, in order to make the determination result more accurate, the corresponding time and space frequency can be selected according to the conditions.