Hashemi Hassan, Nabovati Payam, Khabazkhoob Mehdi, Yekta Abbasali, Emamian Mohammad Hassan, Fotouhi Akbar
Noor Research Center for Ophthalmic Epidemiology, Noor Eye Hospital, Tehran, Iran.
Department of Medical Surgical Nursing, School of Nursing and Midwifery, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Clin Exp Optom. 2018 Jan;101(1):123-128. doi: 10.1111/cxo.12550. Epub 2017 May 17.
The aim was to determine the distribution and associated factors of accommodative amplitude (AA) in six- to 12-year-old children and compare the results with those calculated using Hofstetter's formula.
In a cross-sectional study in 2015, random sampling was done from urban and rural populations of Shahroud, northern Iran. Participating schoolchildren were examined for manifest, cycloplegic and subjective refraction, as well as uncorrected vision and visual acuity. The AA was measured with Donders' push-up method using a ruler. The near point of convergence (NPC) was also measured.
Of the 6,624 selected children, 5,620 participated in the study and after applying the exclusion criteria, the final analyses were done on data from 5,444 schoolchildren. The mean age of the final sample was 9.24 ± 1.71 years (from six to 12 years) and 53.6 per cent (n = 2,919) were boys. Mean measured AA was 14.44 D (95 per cent confidence interval [CI]: 14.33-14.55). In all age groups, the mean measured AA was less than the predicted mean value calculated with the Hofstetter's equation. Mean measured AA was 14.44 D (95 per cent CI: 14.28-14.59) and 14.45 D (95 per cent CI: 14.29-14.6) in boys and girls, respectively (p = 0.926). AA significantly declined with age (coefficient: -0.18, 95 per cent CI: -0.23 to -0.12, p < 0.001). Mean AA in emmetropic, myopic and hyperopic children was 14.31 D, 17.30 D and 14.87 D, respectively. Older age (coefficient = -0.18), living in rural areas (coefficient = -0.48) and NPC (coefficient = 0.47) inversely related with AA and higher AA was associated with a shift of the spherical equivalent refraction toward myopia (coefficient = -0.41).
The differences among groups with different types of refractive error and high AA in children with myopia are important findings of this study. The results of the present study suggest that Hofstetter's formula provides inaccurate AA estimates in children and thus, the interpretation of this index requires further population-based studies in different racial and ethnic groups.
旨在确定6至12岁儿童调节幅度（AA）的分布及相关因素，并将结果与使用霍夫施泰特公式计算得出的结果进行比较。
在2015年的一项横断面研究中，从伊朗北部沙赫鲁德的城乡人口中进行随机抽样。对参与研究的学童进行了显斜视、睫状肌麻痹和主观验光，以及未矫正视力和视力检查。使用直尺通过东德斯上推法测量AA。还测量了集合近点（NPC）。
在6624名选定儿童中，5620名参与了研究，在应用排除标准后，对5444名学童的数据进行了最终分析。最终样本的平均年龄为9.24±1.71岁（6至12岁），53.6%（n = 2919）为男孩。平均测量的AA为14.44D（95%置信区间[CI]：14.33 - 14.55）。在所有年龄组中，平均测量的AA均低于用霍夫施泰特公式计算出的预测平均值。男孩和女孩的平均测量AA分别为14.44D（95%CI：14.28 - 14.59）和14.45D（95%CI：14.29 - 14.6）（p = 0.926）。AA随年龄显著下降（系数：-0.18，95%CI：-0.23至-0.12，p < 0.001）。正视、近视和远视儿童的平均AA分别为14.31D、17.30D和14.87D。年龄较大（系数 = -0.18）、居住在农村地区（系数 = -0.48）和NPC（系数 = 0.47）与AA呈负相关，较高的AA与等效球镜度向近视偏移有关（系数 = -0.41）。
本研究的重要发现是不同类型屈光不正组之间的差异以及近视儿童中较高的AA。本研究结果表明，霍夫施泰特公式在儿童中提供的AA估计不准确，因此，对该指标的解释需要在不同种族和民族群体中进行更多基于人群的研究。
