Great Lakes Eye Care, Saint Joseph, Michigan; Department of Neurology and Ophthalmology, Michigan State University, College of Osteopathic Medicine, East Lansing, Michigan.
Great Lakes Eye Care, Saint Joseph, Michigan.
J Cataract Refract Surg. 2019 Mar;45(3):351-354. doi: 10.1016/j.jcrs.2018.12.026.
To present the Cooke-modified axial length (CMAL) method, which closely approximates sum-of-segments AL. Notably, sum-of-segments AL has been shown to improve predictions of many intraocular lens (IOL) power formulas; however, calculating this AL requires information that is not readily available.
Comparative case series.
Distinct datasets of 215 eyes and 1442 eyes, which were measured before cataract surgery with a commercially available optical biometer (Lenstar LS 900), were identified. The AL measured by this machine was labeled "traditional AL."
Prediction Error.
The CMAL, sum-of-segments AL, and traditional AL methods with Bland-Altman plots and r values were compared, along with graphs of prediction errors.
The CMAL was developed from 215 eyes and evaluated in the 1422-eye validation dataset. The r for CMAL versus the sum-of-segments AL was 0.99983. The predictions based on CMAL were compared with those based on traditional AL using the Hoffer Q, Holladay 1, SRK/T, and Holladay 2 IOL formulas. The CMAL produced more accurate predictions in all four formulas (P < .001). Eyes in all datasets were then combined to create the final recommendation: CMAL = 1.23853 + 0.95855 × traditional AL - 0.05467 × lens thickness (all measurements in millimeters).
A modified AL method (CMAL) was easy to calculate. Using CMAL improved predictions for at least four IOL power prediction formulas, especially at extreme ALs. Caution is advised if using CMAL with other formulas.
介绍 Cooke 改良的眼轴长度（CMAL）方法，该方法与节段和眼轴长度的总和非常接近。值得注意的是，节段和眼轴长度的总和已被证明可以提高许多人工晶状体（IOL）计算公式的预测能力；然而，计算此 AL 需要不易获得的信息。
比较病例系列。
在白内障手术前，使用市售的光学生物测量仪（Lenstar LS 900）分别测量了 215 只眼和 1442 只眼的数据集。该仪器测量的 AL 标记为“传统 AL”。
预测误差。
通过 Bland-Altman 图和 r 值比较了 CMAL、节段和传统 AL 方法，并绘制了预测误差图。
CMAL 由 215 只眼开发，并在 1422 只眼验证数据集中进行了评估。CMAL 与节段和眼轴长度总和的 r 值为 0.99983。基于 CMAL 的预测与基于传统 AL 的预测分别使用 Hoffer Q、Holladay 1、SRK/T 和 Holladay 2 IOL 公式进行比较。在所有四个公式中，CMAL 产生的预测都更准确（P <.001）。然后将所有数据集的眼合并以创建最终建议：CMAL=1.23853+0.95855×传统 AL-0.05467×镜片厚度（所有测量值均以毫米为单位）。
一种改良的 AL 方法（CMAL）易于计算。使用 CMAL 可改善至少四种 IOL 功率预测公式的预测，尤其是在极端 AL 下。如果与其他公式一起使用 CMAL，则需谨慎。
