Feizi Sepehr, Delfazayebaher Siamak, Javadi Mohammad Ali
J Refract Surg. 2018 Jun 1;34(6):379-386. doi: 10.3928/1081597X-20180425-01.
To directly measure internal astigmatism and evaluate its agreement with posterior corneal astigmatism in pseudophakic eyes.
This prospective study enrolled 32 eyes of 32 patients (18 women, 56.3%) who underwent phacoemulsification with implantation of a non-toric monofocal intraocular lens (IOL). Two months postoperatively, posterior corneal astigmatism was measured using a Pentacam Scheimpflug analyzer (Oculus Optikgeräte GmbH, Wetzlar, Germany). Manifest refractive astigmatism was measured after fitting a spherical hard contact lens. This refractive astigmatism that was vertexed to the corneal plane was considered internal astigmatism. The magnitudes of internal and posterior corneal astigmatism were compared. The relationship and agreement between these two astigmatisms were investigated using the Spearman correlation coefficient and Bland-Altman plots, respectively.
The mean patient age was 56.3 ± 9.6 years. IOL decentration or tilt and posterior segment abnormalities were not encountered in any cases postoperatively. The mean refractive astigmatism measured before fitting the hard contact lens was -0.81 ± 0.56 diopters (D). Internal astigmatism (-0.17 ± 0.21 D) was significantly different from posterior corneal astigmatism (-0.30 ± 0.15 D; P = .046). Regression analysis demonstrated a weak association between internal astigmatism and posterior corneal astigmatism (r = 0.22, P = .013). Bland-Altman plots produced 95% limits of agreement for these two astigmatisms from -0.49 to 0.75 D.
A significant but weak correlation was found between the magnitudes of internal astigmatism and posterior corneal astigmatism in the pseudophakic eyes. This result indicates that Pentacam measurement of the posterior cornea did not compare well with a "gold standard" of refraction-derived values. [J Refract Surg. 2018;34(6):379-386.].
直接测量假晶状体眼的内部散光，并评估其与角膜后表面散光的一致性。
这项前瞻性研究纳入了32例患者的32只眼（18例女性，占56.3%），这些患者接受了白内障超声乳化吸除术并植入了非散光单焦点人工晶状体（IOL）。术后两个月，使用Pentacam眼前节分析系统（德国韦茨拉尔Oculus Optikgeräte GmbH公司）测量角膜后表面散光。在配戴球面硬性接触镜后测量明显屈光散光。这种顶点位于角膜平面的屈光散光被视为内部散光。比较内部散光和角膜后表面散光的大小。分别使用Spearman相关系数和Bland-Altman图研究这两种散光之间的关系和一致性。
患者平均年龄为56.3±9.6岁。术后所有病例均未出现IOL偏心或倾斜以及眼后段异常情况。在配戴硬性接触镜之前测量的平均屈光散光为-0.81±0.56屈光度（D）。内部散光（-0.17±0.21 D）与角膜后表面散光（-0.30±0.15 D；P = 0.046）有显著差异。回归分析显示内部散光与角膜后表面散光之间存在弱相关性（r = 0.22，P = 0.013）。Bland-Altman图得出这两种散光的95%一致性界限为-0.49至0.75 D。
在假晶状体眼中，内部散光大小与角膜后表面散光之间存在显著但较弱的相关性。该结果表明，Pentacam对角膜后表面的测量结果与屈光衍生值的“金标准”相比并不理想。[《屈光手术杂志》。2018年；34(6):379 - 386。]
