Hashemi Hassan, Asgari Soheila, Emamian Mohammad Hassan, Mehravaran Shiva, Fotouhi Akbar
*Noor Ophthalmology Research Center, Noor Eye Hospital, Tehran, Iran; †Department of Epidemiology, School of Public Health, Shahroud University of Medical Sciences, Shahroud, Iran; and ‡Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
Cornea. 2015 Nov;34(11):1456-8. doi: 10.1097/ICO.0000000000000595.
To determine 5-year changes in corneal curvature and asphericity in a population-based cohort study of 40 to 64 year olds in Iran.
This report is based on data from the first and second phases of the Shahroud Eye Cohort Study conducted in 2009 and 2014, respectively. In this report, Pentacam data from 3749 people were used. Extracted variables included the maximum and minimum simulated keratometry readings (Kmax and Kmin), the mean radius of sagittal curvature (MRSC) in the central 3- and 2-mm rings between 3 to 11 mm from the center, and the anterior and posterior asphericity in both study phases. In the analysis, repeated-measures analysis of variance was used with a significance level of 0.5.
During the 5-year period of this survey, Kmax and Kmin increased by 0.38 ± 1.95 diopters and 0.46 ± 1.97 diopters, respectively. According to the mean radius of sagittal curvature indices, the cornea steepened in the center up to the 5- to 7-mm ring and flattened in the periphery. The increase in anterior and posterior asphericity was 0.15 ± 0.14 and 0.09 ± 0.14, respectively (all P < 0.001). Women, compared to men, showed more change in Kmax, Kmin, and posterior asphericity (all P < 0.001), but not in anterior asphericity (P = 0.937).
In 40 to 64 year olds, changes are in line with maintaining a prolate ellipsoid shape of the cornea. The corneal surface undergoes greater changes in women than in men. The anterior surface changes more than the posterior.
在一项针对伊朗40至64岁人群的基于人群的队列研究中，确定角膜曲率和非球面性的5年变化情况。
本报告基于分别于2009年和2014年进行的沙赫鲁德眼队列研究第一阶段和第二阶段的数据。在本报告中，使用了3749人的Pentacam数据。提取的变量包括最大和最小模拟角膜曲率计读数（Kmax和Kmin）、距中心3至11毫米处中央3毫米和2毫米环的矢状曲率平均半径（MRSC），以及两个研究阶段的前后非球面性。在分析中，使用了重复测量方差分析，显著性水平为0.5。
在本次调查的5年期间，Kmax和Kmin分别增加了0.38±1.95屈光度和0.46±1.9屈光度。根据矢状曲率指数的平均半径，角膜在中心直至5至7毫米环处变陡，在周边变平。前后非球面性的增加分别为0.15±0.14和0.09±0.14（所有P<0.001）。与男性相比，女性在Kmax、Kmin和后非球面性方面的变化更大（所有P<0.001），但在前非球面性方面没有变化（P=0.937）。
在40至64岁人群中，变化符合维持角膜的长椭球体形状。女性角膜表面的变化比男性更大。前表面的变化大于后表面。
