PURPOSE To investigate the difference between the segmented axial length (AL) and the displayed AL on an optical low-coherence reflectometry (OLCR) biometer and to compare the refractive prediction errors calculated using the segmented and displayed ALs. DESIGN Retrospective case series. PARTICIPANTS Four thousand nine hundred ninety-two eyes from 4992 patients in the theoretical study and 1758 eyes from 1758 patients in the refractive prediction error comparison. METHODS First, we calculated the segmented AL as the sum of geometrical ocular segments converted from the optical path length (OPL) in each medium. To convert the OPL to a geometrical distance in each medium, we used 4 sets of group refractive indices. Then, the mean absolute prediction error (MAE) was calculated with the displayed AL and segmented AL using 6 intraocular lens power formulas: Olsen, Barrett Universal II (Barrett), Haigis, Hoffer Q, Holladay 1, and Sanders-Retzlaff-Kraff trial (SRK/T). MAIN OUTCOME MEASURES Segmented AL, difference in AL (segmented AL minus displayed AL), MAE, and percentage of eyes within 0.5 diopter (D) of error. RESULTS The segmented ALs were up to 0.29 mm longer in short eyes and 0.50 mm shorter in long eyes. The differences in ALs were correlated negatively with the displayed ALs (r values, -0.941 to -0.913; P < 0.001). The MAEs were significantly lower using segmented ALs for all formulas except the Olsen in both the entire group and the long eye subgroup (AL, ≥26 mm) and for the Holladay 1 and Hoffer Q in the short eye subgroup (AL, ≤ 22 mm). Use of segmented ALs produced a greater percentage of eyes within 0.5 D of error for all formulas except the Olsen and Haigis for the entire group, for long eyes, and for the Holladay 1 in short eyes. CONCLUSIONS The segmented ALs were longer in short eyes and shorter in long eyes compared with the displayed ALs calculated with a single group refractive index for the entire eye. The refractive accuracy with segmented ALs was improved in short eyes with the Hoffer Q and Holladay 1 formulas and in long eyes with all formulas except the Olsen formula.

中文翻译：

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对于每个眼段，使用单组折射率与使用不同的折射率来计算轴长：理论研究和屈光结果。

目的研究在光学低相干反射法（OLCR）生物测定仪上的分段轴向长度（AL）和显示的AL之间的差异，并比较使用分段和显示的AL计算的屈光预测误差。设计回顾案系列。参加者在理论研究中来自4992名患者的494只眼和来自1758名患者的1758眼进行了屈光预测误差比较。方法首先，我们将分段的AL计算为从每种介质中的光程长度（OPL）转换而来的几何眼段的总和。要将OPL转换为每种介质中的几何距离，我们使用了4组折射率。然后，使用显示的AL和分段AL使用6个人工晶状体屈光力公式计算平均绝对预测误差（MAE）：Olsen，Barrett Universal II（Barrett），Haigis，Hoffer Q，Holladay 1和Sanders-Retzlaff-Kraff试验（SRK） / T）。主要观察指标分段的AL，AL的差异（分段的AL减去显示的AL），MAE以及误差在0.5屈光度（D）以内的眼睛百分比。结果分段的AL在短眼中长0.29 mm，在长眼中短0.50 mm。AL的差异与显示的AL呈负相关（r值，-0.941至-0.913； P <0.001）。除整个组和长眼亚组（AL，≥26mm）中的Olsen以及短眼亚组（AL，≤22 mm）中的Holladay 1和Hoffer Q外，对于所有配方，使用分段AL的MAE均显着降低）。除了整个组的奥尔森（Olsen）和海吉斯（Haigis），长眼睛和短眼Holladay 1的使用，对于所有配方，使用分段AL会产生更大百分比的眼睛，误差在0.5 D以内。结论与用整个眼睛的单组折射率计算的显示AL相比，分段AL在短眼中较长，在长眼中较短。使用Hoffer Q和Holladay 1配方的短眼提高了分段AL的屈光准确度，使用Olsen配方的所有配方提高了长视的屈光精度。结论与用整个眼睛的单组折射率计算的显示AL相比，分段AL在短眼中较长，在长眼中较短。使用Hoffer Q和Holladay 1配方的短眼提高了分段AL的屈光准确度，使用Olsen配方的所有配方提高了长视的屈光精度。结论与用整个眼睛的单组折射率计算的显示AL相比，分段AL在短眼中较长，在长眼中较短。使用Hoffer Q和Holladay 1配方的短眼提高了分段AL的屈光准确度，使用Olsen配方的所有配方提高了长视的屈光精度。