Dobson Velma, Harvey Erin M, Clifford-Donaldson Candice E, Green Tina K, Miller Joseph M
Department of Ophthalmology and Vision Science, The University of Arizona, Tucson, Arizona, USA.
Optom Vis Sci. 2010 May;87(5):330-6. doi: 10.1097/OPX.0b013e3181d951c8.
To determine whether reduced astigmatism-corrected acuity for vertical (V) and/or horizontal (H) gratings and/or meridional amblyopia (MA) are present before 3 years of age in children who have with-the-rule astigmatism.
Subjects were 448 children, 6 months through 2 years of age with no known ocular abnormalities other than with-the-rule astigmatism, who were recruited through Women, Infants and Children clinics on the Tohono O'odham reservation. Children were classified as non-astigmats (< or =2.00 diopters) or astigmats (>2.00 diopters) based on right eye non-cycloplegic autorefraction measurements (Welch Allyn SureSight). Right eye astigmatism-corrected grating acuity for V and H stimuli was measured using the Teller Acuity Card procedure while children wore cross-cylinder lenses to correct their astigmatism or plano lenses if they had no astigmatism.
Astigmatism-corrected acuity for both V and H gratings was significantly poorer in the astigmats than in the non-astigmats, and the reduction in acuity for astigmats was present for children in all three age groups examined (6 months to <1 year, 1 to <2 years, and 2 to <3 years). There was no significant difference in V-H grating acuity (no evidence of MA) for the astigmatic group as a whole, or when data were analyzed for each age group.
Even in the youngest age group, astigmats tested with astigmatism correction showed reduced acuity for both V and H gratings, which suggests that astigmatism is having a negative influence on visual development. We found no evidence of orientation-related differences in astigmatism-corrected grating acuity, indicating either that MA does not develop before 3 years of age, or that most of the astigmatic children had a type of astigmatism, i.e., hyperopic, that has proven to be less likely than myopic or mixed astigmatism to result in MA.
确定在有顺规散光的儿童3岁之前，垂直（V）和/或水平（H）光栅的散光矫正视力降低及/或子午线弱视（MA）是否存在。
研究对象为448名6个月至2岁的儿童，他们除顺规散光外无其他已知眼部异常，通过托霍诺奥德汉姆保留地的妇女、婴儿和儿童诊所招募而来。根据右眼非睫状肌麻痹自动验光测量结果（伟伦SureSight），将儿童分为非散光组（≤2.00屈光度）或散光组（>2.00屈光度）。当儿童佩戴交叉圆柱镜矫正散光时，使用泰勒视力卡片程序测量右眼矫正散光后的V和H刺激光栅视力；若儿童无散光，则佩戴平光镜进行测量。
散光组V和H光栅的矫正视力均显著低于非散光组，且在所有三个检查年龄组（6个月至<1岁、1至<2岁、2至<3岁）的儿童中，散光组的视力均有所下降。散光组整体的V - H光栅视力无显著差异（无MA证据），各年龄组数据分析时亦是如此。
即使在最年幼的年龄组中，经散光矫正测试的散光儿童V和H光栅视力均降低，这表明散光对视功能发育有负面影响。我们未发现矫正散光后光栅视力存在与方向相关的差异，这表明要么MA在3岁之前不会发生，要么大多数散光儿童患有一种散光类型，即远视散光，已证实这种散光比近视或混合散光导致MA的可能性更小。
