扫描翻转图像视觉诱发电位视力与对数视力表视力的比较

目的 对扫描图像视觉诱发电位视力(SPVER视力)与对数视力表视力进行比较。方法比较50例受试者的视力表和SPVER视力。在SPVER视力的测定中用了8个不同空间频率的光栅条纹连续扫描，所得数据经离散傅立叶分析后，获得振幅一空间频率曲线，并由外推法估计其视力。结果SPVER视力与视力表视力的总体相关系数r=0．699，在视力表视力大于0．5时，SPVER视力有低估现象，而在视力表视力小于0．5时SPVER视力有高估现象。结论SPVER视力与视力表视力有良好的相关性。由于视力表视力和SPVER视力所用于评估视力的指标不同，使两者结果不完全相同。

Sweep pattern visualevoked response acuity vs logarithmic visual acuity

Objective To compare the sweep pattern visual evoked response acuity SPVER-A with the logarithmic visual acuity. Methods SPVER-A and logarithmic visual acuity were measured and compared in 50 people. 8-squared vertical gratings were presented as stimuli continuously. The responses were averaged and displayed through the discrete fourier transform on the monitor display. The SPVER acuity was determined by extrapolating the SPVER amplitude-spatial frequency function to baseline. Results The overall correlation was r = 0. 699 between the SPVER-A and logarithmic visual acuity. Underestimation of acuity by the SPVER when the logarithmic visual acuity is better than 0. 5. On the other hand, when the logarithmic visual acuity is worse than 0. 5 the SPVER-A was overestimated. Conclusion SPVER-A has a good correlation to logarithmic acuity. The difference between two methods may indicate that the grating acuity and logarithmic /visual acuity activate different system.