McKendrick Allison M, Johnson Chris A, Anderson Andrew J, Fortune Brad
Discoveries in Sight, Devers Eye Institute, Legacy Clinical Research and Technology Center, Portland, OR 97208-3950, USA.
Invest Ophthalmol Vis Sci. 2002 May;43(5):1393-9.
In 1993, Piltz et al. observed that foveal vernier acuity thresholds for achromatic targets are elevated in patients with glaucoma. This study was undertaken to explore whether such elevated thresholds are present when subject groups are measured with targets of effectively equivalent contrast. Vernier acuity measures were also obtained with short-wavelength and frequency-doubled stimuli, to assess spatial hyperacuity performance in the short-wavelength-sensitive and magnocellular pathways, respectively.
Twenty patients with glaucoma and 19 subjects with normal vision participated. All subjects had visual acuity of 20/25 or better. Achromatic two-dot vernier thresholds were obtained for 90% contrast dots. In addition, individual contrast thresholds to the achromatic dots were measured for each subject, and vernier thresholds were measured at 4, 8, 12, and 16 times contrast threshold. Short-wavelength vernier acuity thresholds were measured for blue dots presented on a bright yellow background. The stimulus for the frequency-doubling grating vernier acuity task was a 90% contrast, 1-cyc/deg, 25-Hz sinusoidal grating.
The glaucoma group demonstrated significantly higher foveal vernier acuity thresholds than control subjects for the blue-on-yellow stimulus (P = 0.002) and frequency-doubling grating stimulus (P < 0.001). No significant difference in vernier acuity between groups was found for the 90% contrast achromatic dots (P = 0.09), however a significant difference was found for the normalized contrast targets (P = 0.04).
Vernier acuity tasks can be used to demonstrate abnormal foveal function in glaucoma. Testing with visual-function-specific stimuli may be effective in identifying such dysfunction. Vernier acuity, or other similar hyperacuity tasks that assess spatial sampling, may be useful in the detection of early glaucomatous damage, before it is detected with traditional perimetric tests.
1993年，皮尔茨等人观察到青光眼患者对于消色差目标的中央凹游标视力阈值升高。本研究旨在探讨当用有效对比度相当的目标对受试组进行测量时，是否也存在这种升高的阈值。还使用短波和倍频刺激获得了游标视力测量结果，以分别评估短波敏感通路和大细胞通路中的空间超敏锐度表现。
20名青光眼患者和19名视力正常的受试者参与了研究。所有受试者的视力均为20/25或更好。获得了90%对比度圆点的消色差两点游标阈值。此外，还测量了每个受试者对消色差圆点的个体对比度阈值，并在对比度阈值的4、8、12和16倍时测量了游标阈值。测量了在亮黄色背景上呈现的蓝色圆点的短波游标视力阈值。倍频光栅游标视力任务的刺激是一个90%对比度、1周/度、25赫兹的正弦光栅。
青光眼组在黄底蓝刺激（P = 0.002）和倍频光栅刺激（P < 0.001）下的中央凹游标视力阈值显著高于对照组。对于90%对比度的消色差圆点，两组之间的游标视力无显著差异（P = 0.09），然而对于归一化对比度目标则存在显著差异（P = 0.04）。
游标视力任务可用于证明青光眼患者中央凹功能异常。使用视觉功能特异性刺激进行测试可能有助于识别这种功能障碍。游标视力或其他类似的评估空间采样的超敏锐度任务，可能在传统视野检查检测到早期青光眼损害之前，对其检测有用。
