Tulunay-Keesey U, Brooks B R, Kukuljan R, Ver Hoeve J N
Ophthalmology Department, University of Wisconsin, Madison 53705-2280.
Vision Res. 1994 Jan;34(1):123-36. doi: 10.1016/0042-6989(94)90263-1.
Spatiotemporal contrast sensitivity at three orientations, vertical, horizontal and oblique, was studied in 18 patients with clinically definite and laboratory-confirmed definite multiple sclerosis (MS). Nineteen age-matched control subjects were also studied under identical experimental conditions. Contrast thresholds for detecting steady and counterphase modulated (5 Hz) gratings ranging in spatial frequency from 0.5 to 12 c/deg were measured by a modified psychophysical method of limits. With the exception of two patients (three eyes) whose Snellen acuity scores were 20/70, all observers had acuity scores of 20/30 or better. All subjects were corrected for astigmatism. Orientation, spatial frequency and temporal frequency interacted differently in determining contrast sensitivity in the two groups of observers. For the controls, an oblique effect was present for both the steady and counterphase modulated gratings of high spatial frequencies, and there was no orientation-dependent loss of sensitivity for low spatial frequencies. For the observers with MS, there was no oblique effect, but sensitivity was dependent on orientation for the low spatial frequencies. Most patients with MS had reduced contrast sensitivity, compared to the controls, at one or more orientations. Counterphase modulation increased sensitivity to the low spatial frequencies and decreased sensitivity to the high spatial frequencies for both normal controls and patients with MS. In patients with MS this effect of temporal modulation on contrast sensitivity was markedly enhanced.
对18例临床确诊且经实验室证实为明确多发性硬化症（MS）的患者，研究了垂直、水平和倾斜三个方向上的时空对比敏感度。在相同实验条件下，还对19名年龄匹配的对照受试者进行了研究。采用改良的极限心理物理学方法，测量了空间频率范围为0.5至12周/度的检测稳定和反相调制（5赫兹）光栅的对比阈值。除两名Snellen视力评分为20/70的患者（三只眼）外，所有观察者的视力评分均为20/30或更好。所有受试者均进行了散光矫正。在两组观察者中，方向、空间频率和时间频率在确定对比敏感度时的相互作用方式不同。对于对照组，高空间频率的稳定和反相调制光栅均存在倾斜效应，而低空间频率不存在与方向相关的敏感度损失。对于MS患者，不存在倾斜效应，但低空间频率的敏感度取决于方向。与对照组相比，大多数MS患者在一个或多个方向上的对比敏感度降低。对于正常对照组和MS患者，反相调制均提高了对低空间频率的敏感度，并降低了对高空间频率的敏感度。在MS患者中，时间调制对对比敏感度的这种影响明显增强。
