From Implant Research and Development (Canovas, Alarcon, Rosén, Piers), Abbott Medical Optics, Inc., Groningen BV, the Netherlands; Clinical Research (Kasthurirangan), Abbott Medical Optics, Inc., Santa Ana, California, and Cullen Eye Institute (Koch), Baylor College of Medicine, Houston, Texas, USA; Department of Ophthalmology and Vision Science (Ma), University of Toronto, Toronto, Ontario, Canada.
From Implant Research and Development (Canovas, Alarcon, Rosén, Piers), Abbott Medical Optics, Inc., Groningen BV, the Netherlands; Clinical Research (Kasthurirangan), Abbott Medical Optics, Inc., Santa Ana, California, and Cullen Eye Institute (Koch), Baylor College of Medicine, Houston, Texas, USA; Department of Ophthalmology and Vision Science (Ma), University of Toronto, Toronto, Ontario, Canada.
J Cataract Refract Surg. 2018 Feb;44(2):168-174. doi: 10.1016/j.jcrs.2017.11.008. Epub 2018 Mar 7.
To assess the accuracy of toric intraocular lens (IOL) power calculations of a new algorithm that incorporates the effect of posterior corneal astigmatism (PCA).
Abbott Medical Optics, Inc., Groningen, the Netherlands.
Retrospective case report.
In eyes implanted with toric IOLs, the exact vergence formula of the Tecnis toric calculator was used to predict refractive astigmatism from preoperative biometry, surgeon-estimated surgically induced astigmatism (SIA), and implanted IOL power, with and without including the new PCA algorithm. For each calculation method, the error in predicted refractive astigmatism was calculated as the vector difference between the prediction and the actual refraction. Calculations were also made using postoperative keratometry (K) values to eliminate the potential effect of incorrect SIA estimates.
The study comprised 274 eyes. The PCA algorithm significantly reduced the centroid error in predicted refractive astigmatism (P < .001). With the PCA algorithm, the centroid error reduced from 0.50 @ 1 to 0.19 @ 3 when using preoperative K values and from 0.30 @ 0 to 0.02 @ 84 when using postoperative K values. Patients who had anterior corneal against-the-rule, with-the-rule, and oblique astigmatism had improvement with the PCA algorithm. In addition, the PCA algorithm reduced the median absolute error in all groups (P < .001).
The use of the new PCA algorithm decreased the error in the prediction of residual refractive astigmatism in eyes implanted with toric IOLs. Therefore, the new PCA algorithm, in combination with an exact vergence IOL power calculation formula, led to an increased predictability of toric IOL power.
评估一种新算法对后角膜散光（PCA）影响的计算的准确性，该算法可用于计算散光人工晶状体（IOL）的屈光度。
荷兰格罗宁根 Abbott Medical Optics，Inc.。
回顾性病例报告。
在植入散光 IOL 的眼中，使用 Tecnis 散光计算器的确切屈光公式，根据术前生物测量、外科医生估计的手术引起的散光（SIA）和植入的 IOL 屈光度，预测屈光性散光，包括和不包括新的 PCA 算法。对于每种计算方法，预测屈光性散光的误差计算为预测值与实际屈光值之间的向量差。还使用术后角膜曲率计（K）值进行计算，以消除不正确的 SIA 估计的潜在影响。
该研究包括 274 只眼。PCA 算法显著降低了预测屈光性散光的质心误差（P <.001）。使用术前 K 值时，PCA 算法将质心误差从 0.50 @ 1 降低到 0.19 @ 3，使用术后 K 值时将质心误差从 0.30 @ 0 降低到 0.02 @ 84。对于前角膜逆规散光、规则散光和斜散光的患者，PCA 算法有改善。此外，PCA 算法降低了所有组的中位绝对误差（P <.001）。
使用新的 PCA 算法降低了植入散光 IOL 后残余屈光性散光预测的误差。因此，新的 PCA 算法与精确的屈光力 IOL 计算公式相结合，提高了散光 IOL 屈光度的预测能力。
