Guangdong Eye Institute, Guangdong Academy of Medical Sciences, Guangzhou, China.
J Cataract Refract Surg. 2010 Jan;36(1):87-96. doi: 10.1016/j.jcrs.2009.07.011.
To evaluate an algorithm for corneal power estimation in intraocular lens (IOL) power calculation after myopic laser refractive surgery using direct corneal measurements.
International Vision Correction Research Centre, University of Heidelberg, Heidelberg, Germany.
Corneal parameters in normal eyes and eyes of refractive surgery cases were evaluated by rotating Scheimpflug imaging. Corneal optical power (K(optical)) calculated by a Gaussian optics formula was simplified as K(optical) = K(anterior) + K(2) (K(anterior) = anterior corneal power; K(posterior) = posterior corneal power; K(2) = K(posterior)--K(anterior) x K(posterior) x corneal thickness/1.376). The variation and change in K(2) induced by refractive surgery were analyzed. A corrective algorithm to calculate K(optical) using mean K(2) (-6.10 diopters [D]), K(corrective) = 1.114 x measured K - 6.10, was derived based on statistical analysis, which was in accordance with the modified Maloney method. The IOL power after refractive surgery was calculated using K(corrective).
The mean K(2) of normal and post-refractive corneas was -6.10 +/- 0.23 D and -6.16 +/- 0.17 D, respectively (P = .17). The mean refractive surgery-induced change in K(2) was -0.06 +/- 0.10 D. The variations in K(2) were small (95% confident interval, -6.55 to -5.65 [normal cornea]; -6.48 to -5.70 [pre-refractive]; - 6.49 to -5.83 [post-refractive)]. Using K(corrective) for IOL power calculation in post-refractive cases yielded mean absolute prediction errors of 0.58 +/- 0.52 D (Haigis), 0.59 +/- 0.49 D (double-K Hoffer Q), and 0.58 +/- 0.47 D (double-K SRK/T).
The algorithm that induced low error in corneal power estimation was relatively reliable in IOL calculation after myopic laser refractive surgery.
No author has a financial or proprietary interest in any material or method mentioned.
评估一种使用直接角膜测量法估算近视激光屈光手术后眼内晶状体（IOL）屈光力计算中角膜屈光力的算法。
德国海德堡大学国际视觉矫正研究中心。
使用旋转式 Scheimpflug 成像评估正常眼和屈光手术病例的角膜参数。通过高斯光学公式计算的角膜光学屈光力（K（光学））简化为 K（光学）= K（前）+ K（2）（K（前）=前角膜屈光力；K（后）=后角膜屈光力；K（2）= K（后）- K（前）x K（后）x 角膜厚度/1.376）。分析屈光手术后 K（2）的变化和变化。基于统计分析，得出了一种使用平均 K（2）（-6.10 屈光度[D]）计算 K（光学）的矫正算法，K（矫正）= 1.114 x 测量 K - 6.10，与改良的 Maloney 方法一致。使用 K（矫正）计算屈光手术后的 IOL 屈光力。
正常和屈光后角膜的平均 K（2）分别为-6.10 +/- 0.23 D 和-6.16 +/- 0.17 D（P =.17）。平均屈光手术引起的 K（2）变化为-0.06 +/- 0.10 D。K（2）的变化较小（95%置信区间，-6.55 至-5.65[正常角膜]；-6.48 至-5.70[术前]；-6.49 至-5.83[术后]）。在屈光手术后病例中使用 K（矫正）进行 IOL 屈光力计算，平均绝对预测误差分别为 0.58 +/- 0.52 D（Haigis）、0.59 +/- 0.49 D（双-K Hoffer Q）和 0.58 +/- 0.47 D（双-K SRK/T）。
在近视激光屈光手术后，诱导角膜屈光力估算误差较小的算法在 IOL 计算中相对可靠。
