Norgett Yvonne, Siderov John
Department of Vision and Hearing Sciences, Anglia Ruskin University, East Road, Cambridge CB11PT, United Kingdom.
Optom Vis Sci. 2011 Aug;88(8):920-7. doi: 10.1097/OPX.0b013e31821bd2d3.
The aim of this study was to investigate the effect of test design (crowding) and age on visual acuity in a sample of young children.
Vision was measured in 103 children aged between 4 and 9 years using five different visual acuity tests. The tests included three crowded tests: logMAR Crowded test, the Sonksen logMAR test, and the Crowded Kay Picture test, and two single optotype tests: the Single Kay Picture and Sheridan Gardiner tests. Tests were presented in a random order using standardized instructions and a defined end-point. Results were analyzed in two age groups, younger (4 to 6 years) and older (7 to 9 years).
In both groups, there was a significant main effect of test on acuity (younger: F = 63.92, dF = 4, p < 0.001; older: F = 63.59, dF = 4, p < 0.001). In the younger group, an effect of crowding was seen in all three crowded tests, but in the older group, an effect of crowding was seen only in the crowded letter tests. In both groups, mean acuity was lowest with the logMAR Crowded test, which has the closest interoptotype spacing (0.5), slightly higher with the Sonksen test (with interoptotype spacing of 1.0) and highest with the single optotype tests (no crowding). More crowding was seen in the younger children.
Our results show that maturation of line acuity is still taking place between the ages of 4 and 9 years. Measured acuity is affected by the amount of contour interaction induced by the type of optotype (letter or picture) and by the interoptotype separation. Another factor, probably a maturation of gaze control or selective attention is responsible for the reduction in crowding with age.
本研究旨在调查测试设计（拥挤程度）和年龄对幼儿样本视力的影响。
使用五种不同的视力测试方法对103名年龄在4至9岁之间的儿童进行视力测量。测试包括三种拥挤测试：对数最小分辨角（logMAR）拥挤测试、桑克森对数最小分辨角测试和拥挤凯氏图片测试，以及两种单视标测试：单凯氏图片测试和谢里丹·加德纳测试。测试按照随机顺序进行，使用标准化的指导语和明确的终点。结果在两个年龄组中进行分析，较年轻组（4至6岁）和较年长组（7至9岁）。
在两个组中，测试对视力均有显著的主效应（较年轻组：F = 63.92，自由度 = 4，p < 0.001；较年长组：F = 63.59，自由度 = 4，p < 0.001）。在较年轻组中，在所有三种拥挤测试中都观察到了拥挤效应，但在较年长组中，仅在拥挤字母测试中观察到了拥挤效应。在两个组中，对数最小分辨角拥挤测试的平均视力最低，该测试的视标间距最接近（0.5），桑克森测试（视标间距为1.0）的平均视力略高，单视标测试（无拥挤）的平均视力最高。较年幼的儿童中观察到更多的拥挤现象。
我们的结果表明，在4至9岁之间，视力敏锐度仍在发育。测量的视力受到视标类型（字母或图片）引起的轮廓相互作用量以及视标间距的影响。另一个因素，可能是注视控制或选择性注意力的成熟，导致了随着年龄增长拥挤效应的降低。
