Miyake Toshiyuki, Shimizu Kimiya, Kamiya Kazutaka
Department of Ophthalmology, University of Kitasato School of Medicine, Kanagawa, Japan.
PLoS One. 2015 Jan 27;10(1):e0117194. doi: 10.1371/journal.pone.0117194. eCollection 2015.
To investigate the distribution of posterior corneal astigmatism in eyes with with-the-rule (WTR) and against-the-rule (ATR) anterior corneal astigmatism.
We retrospectively examined six hundred eight eyes of 608 healthy subjects (275 men and 333 women; mean age ± standard deviation, 55.3 ± 20.2 years). The magnitude and axis orientation of anterior and posterior corneal astigmatism were determined with a rotating Scheimpflug system (Pentacam HR, Oculus) when we divided the subjects into WTR and ATR anterior corneal astigmatism groups.
The mean magnitudes of anterior and posterior corneal astigmatism were 1.14 ± 0.76 diopters (D), and 0.37 ± 0.19 D, respectively. We found a significant correlation between the magnitudes of anterior and posterior corneal astigmatism (Pearson correlation coefficient r = 0.4739, P<0.001). In the WTR anterior astigmatism group, we found ATR astigmatism of the posterior corneal surface in 402 eyes (96.6%). In the ATR anterior astigmatism group, we found ATR posterior corneal astigmatism in 82 eyes (73.9%). Especially in eyes with ATR anterior corneal astigmatism of 1 D or more and 1.5 D or more, ATR posterior corneal astigmatism was found in 28 eyes (59.6%) and 9 eyes (42.9%), respectively.
WTR anterior astigmatism and ATR posterior astigmatism were found in approximately 68% and 91% of eyes, respectively. The magnitude and the axis orientation of posterior corneal astigmatism were not constant, especially in eyes having high ATR anterior corneal astigmatism, as is often the case in patients who have undergone toric IOL implantation.
研究顺规（WTR）和逆规（ATR）角膜前表面散光眼的角膜后表面散光分布情况。
我们回顾性检查了608名健康受试者的608只眼（275名男性和333名女性；平均年龄±标准差，55.3±20.2岁）。当我们将受试者分为WTR和ATR角膜前表面散光组时，使用旋转Scheimpflug系统（Pentacam HR，Oculus）确定角膜前、后表面散光的度数和轴向。
角膜前、后表面散光的平均度数分别为1.14±0.76屈光度（D）和0.37±0.19 D。我们发现角膜前、后表面散光度数之间存在显著相关性（Pearson相关系数r = 0.4739，P<0.001）。在WTR角膜前表面散光组中，402只眼（96.6%）的角膜后表面为ATR散光。在ATR角膜前表面散光组中，82只眼（73.9%）的角膜后表面为ATR散光。特别是在角膜前表面ATR散光为1 D及以上和1.5 D及以上的眼中，分别有28只眼（59.6%）和9只眼（42.9%）的角膜后表面为ATR散光。
分别在约68%和91%的眼中发现WTR角膜前表面散光和ATR角膜后表面散光。角膜后表面散光的度数和轴向并不恒定，尤其是在角膜前表面ATR散光较高的眼中，这在接受散光型人工晶状体植入的患者中很常见。
