Heydarian Samira, Sardari Sara, Heidari Zahra, Yekta Abbas Ali, Ostadimoghaddam Hadi, Khabazkhoob Mehdi
Department of Rehabilitation Science, School of Allied Medical Sciences, Mazandaran University of Medical Sciences, Sari, Iran.
Noor Research Center for Ophthalmic Epidemiology, Noor Eye Hospital, Tehran, Iran.
J Curr Ophthalmol. 2020 Dec 12;32(4):355-360. doi: 10.4103/JOCO.JOCO_8_20. eCollection 2020 Oct-Dec.
To determine the distribution of residual and corneal astigmatism (CA) in children aged 6-18 years and their relationship with age, sex, spherical equivalent, and biometric parameters.
In this cross-sectional study, multi-stage stratified cluster sampling was done to select students from Dezful, a city in Southwestern Iran. Examinations included the measurement of visual acuity with and without optical correction, refraction with and without cycloplegia, and biometry using the Biograph (Lenstar, Germany). The main outcomes in this report were corneal and residual astigmatism. The CA was measured by Biograph (difference between k1 and k2), and residual astigmatism was calculated using Alpine method. The power vector method was applied to analyze the data of astigmatism.
Of 864 students that were selected, 683 (79.1%) participated in the study. The mean residual and CA were -0.84 diopter (D) and -0.85 D, respectively. According to the results of J0 and J45 vectors, residual astigmatism was -0.33 D and 0.04 D, and CA was 0.38 D and 0.01 D, respectively. With-the-rule (WTR), against-the-rule (ATR), and oblique astigmatism were seen in 3.4%, 66.8%, and 4.5% of the children with residual astigmatism and 67.94%, 1.3%, and 1.5% of the children with CA. Residual astigmatism decreased with an increase in spherical refractive error, whereas CA increased with an increase in spherical refractive error.
The results of the present study showed a high prevalence and amount of residual astigmatism with ATR pattern among the 6-18-year-old population and the compensatory effect of this type of astigmatism on CA that mostly followed a WTR pattern.
确定6至18岁儿童残余散光和角膜散光（CA）的分布情况及其与年龄、性别、等效球镜度和生物测量参数的关系。
在这项横断面研究中，采用多阶段分层整群抽样方法从伊朗西南部城市迪兹富尔选取学生。检查包括有和无光学矫正时的视力测量、有和无睫状肌麻痹时的验光以及使用Biograph（德国Lenstar）进行的生物测量。本报告的主要结果是角膜散光和残余散光。通过Biograph测量CA（k1和k2之间的差值），并使用阿尔派方法计算残余散光。应用屈光力矢量法分析散光数据。
在选取的864名学生中，683名（79.1%）参与了研究。平均残余散光和CA分别为-0.84屈光度（D）和-0.85 D。根据J0和J45矢量的结果，残余散光分别为-0.33 D和0.04 D，CA分别为0.38 D和0.01 D。在有残余散光的儿童中，顺规散光（WTR）、逆规散光（ATR）和斜向散光分别见于3.4%、66.8%和4.5%的儿童；在有CA的儿童中，分别见于67.94%、1.3%和1.5%的儿童。残余散光随球镜屈光不正的增加而降低，而CA随球镜屈光不正的增加而增加。
本研究结果显示，在6至18岁人群中，ATR模式的残余散光患病率和度数较高，且这种类型的散光对大多遵循WTR模式的CA有代偿作用。
