Cornell E H, McDonnell P M
Invest Ophthalmol Vis Sci. 1986 Sep;27(9):1417-20.
Measurement of duration of fixation was used to assess the ability of 6-, 12-, 24-, and 36-week-old infants to discriminate black-and-white square-wave gratings from a homogeneous gray field at a distance of 20 ft (6.1 m). Acuity was estimated as the smallest stripe width detectable by at least 18 of the 24 infants in a given age group. The strip width was considered detectable if it was fixated longer than a homogenous gray field. The results are consistent with estimates of infants' threshold acuity obtained at target distances less than 5 feet (1.5 m). Because of the 20-ft viewing distance, these infants' acuity in Snellen notation can be more confidently estimated.
通过测量注视持续时间来评估6周、12周、24周和36周大的婴儿在20英尺（6.1米）距离处辨别黑白方波光栅与均匀灰色背景的能力。视力被估计为在给定年龄组的24名婴儿中至少18名能够检测到的最小条纹宽度。如果条纹被注视的时间长于均匀灰色背景，则认为该条纹宽度是可检测到的。这些结果与在小于5英尺（1.5米）的目标距离下获得的婴儿阈限视力估计值一致。由于采用了20英尺的观察距离，因此可以更有把握地估计这些婴儿的斯内伦视力表视力。
