Schmid Katrina L, Robert Iskander D, Li Roger W H, Edwards Marion H, Lew John K F
Centre for Eye Research, School of Optometry, Queensland University of Technology, Kelvin Grove Campus, Victoria Park Road, Kelvin Grove, Brisbane, Queensland 4059, Australia.
Vision Res. 2002 Jan;42(2):239-47. doi: 10.1016/s0042-6989(01)00277-2.
There is some suggestion that the ability to detect blur may be altered in adults with myopia. Here, we address the question of whether children with myopia have worse blur detection than other children, and whether blur detection in myopic children is related to the rate of myopia progression. We recruited 20 myopes and 20 non-myopes aged between 8 and 12 years. Refractive errors, visual acuity, and contrast sensitivity were measured and the change in refractive error over the past year calculated from clinic records. Blur detection thresholds for two different types of black and white targets (text and scenes), two illumination conditions and two testing protocols were determined using a computer-based forced-choice testing procedure. The two testing protocols used were: (i) dual image presentation where subjects were asked to choose the clearer of the two images, one image always having zero blur, and (ii) single image presentation in which the subject reported whether the image was clear or blurred. Blur discrimination ability under all tested conditions was similar for both refractive error groups. Blur detection thresholds were 0.27+/-0.15 D (myopes) and 0.24+/-0.07 D (non-myopes) for text images. Thresholds were similar when measured with a one log unit reduction in lighting: 0.27+/-0.31 D compared to 0.23+/-0.14 D. Blur detection thresholds were greater for photographic scenes (myopes 0.41+/-0.36 D, non-myopes 0.44+/-0.36 D) and when only a single text image (myopes 0.51+/-0.21 D, non-myopes 0.59+/-0.01 D) was presented, but this increase was measured in both refractive error groups. There was no correlation between blur thresholds and refractive error magnitude, refractive error progression over the past year, or contrast sensitivity. We found that the blur detection ability showed greater individual variation in myopic children. Further work is required to determine whether blur detection ability is of relevance to myopia development.
有迹象表明，近视成年人检测模糊的能力可能会发生改变。在此，我们探讨近视儿童的模糊检测能力是否比其他儿童更差，以及近视儿童的模糊检测与近视进展速度是否相关。我们招募了20名8至12岁的近视儿童和20名非近视儿童。测量了屈光不正、视力和对比敏感度，并根据临床记录计算过去一年的屈光不正变化。使用基于计算机的强制选择测试程序，确定了两种不同类型的黑白目标（文本和场景）、两种照明条件和两种测试方案下的模糊检测阈值。所使用的两种测试方案为：（i）双图像呈现，即要求受试者选择两张图像中更清晰的一张，其中一张图像始终无模糊；（ii）单图像呈现，即受试者报告图像是清晰还是模糊。在所有测试条件下，两个屈光不正组的模糊辨别能力相似。文本图像的模糊检测阈值为0.27±0.15 D（近视儿童）和0.24±0.07 D（非近视儿童）。在光照降低一个对数单位时测量的阈值相似：分别为0.27±0.31 D和0.23±0.14 D。摄影场景的模糊检测阈值更高（近视儿童为0.41±0.36 D，非近视儿童为0.44±0.36 D），当只呈现单个文本图像时也是如此（近视儿童为0.51±0.21 D，非近视儿童为0.59±0.01 D），但两个屈光不正组均有这种增加。模糊阈值与屈光不正度数、过去一年的屈光不正进展或对比敏感度之间没有相关性。我们发现，近视儿童的模糊检测能力表现出更大的个体差异。需要进一步开展工作来确定模糊检测能力是否与近视发展相关。
