Alexander K R, Derlacki D J, Fishman G A
Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago College of Medicine 60612, USA.
Vision Res. 1995 May;35(10):1495-9. doi: 10.1016/0042-6989(95)98729-s.
This study examined the quantitative relationship between foveal visual acuity and contrast sensitivity for large-letter optotypes in a group of patients with retinitis pigmentosa (RP), in order to assess more completely the extent of foveal vision loss in this group of hereditary retinal dystrophies. High-contrast visual acuity and large-letter contrast sensitivity were measured with a computer-based testing system and with commercially available letter charts (Lighthouse Distance Visual Acuity Test; Pelli-Robson Contrast Sensitivity Chart). Findings from 20 patients with typical RP or Usher syndrome were compared with those from 15 age-similar control subjects with normal vision. On both the computer-based test and the chart tests, the patients with RP showed approximately equal reductions in visual acuity and large-letter contrast sensitivity. However, intersubject controls was greater for contrast sensitivity than for visual acuity on both test protocols. As a result, the patients with RP required a greater reduction in contrast sensitivity than in acuity to exceed the normal range, indicating that visual acuity was the more sensitive index of the loss of foveal visual function.
本研究调查了一组视网膜色素变性（RP）患者中，大字母视标中心凹视力与对比敏感度之间的定量关系，以便更全面地评估这组遗传性视网膜营养不良患者中心凹视力丧失的程度。使用基于计算机的测试系统和市售字母视力表（灯塔远距离视力测试；佩利-罗布森对比敏感度表）测量高对比度视力和大字母对比敏感度。将20例典型RP或Usher综合征患者的结果与15例年龄相仿、视力正常的对照受试者的结果进行比较。在基于计算机的测试和视力表测试中，RP患者的视力和大字母对比敏感度下降程度大致相同。然而，在两种测试方案中，受试者间对比敏感度的变异性均大于视力。因此，RP患者的对比敏感度需要比视力更大程度的下降才能超出正常范围，这表明视力是中心凹视觉功能丧失更敏感的指标。
