Helaly Hany Ahmed, Gaballah Karim Abdellatif, Ragab Ahmed Mahmoud, Ibrahim Tamer Moussa
Ophthalmology Department, Faculty of Medicine, Alexandria University, Alexandria, Egypt.
Ophthalmology Department, Faculty of Medicine, Helwan University, Cairo, Egypt.
Clin Ophthalmol. 2025 Mar 8;19:785-793. doi: 10.2147/OPTH.S511337. eCollection 2025.
To evaluate the sum of segments (SOS) biometry in modern intraocular lens power (IOL) calculation formulas for long eyes.
This was a retrospective case series that included 177 eyes from 177 patients with axial length (AL) ≥ 24.5 mm. Preoperative AL measurements were performed using the ARGOS (Alcon, Inc). This study used 2 formulas: the Barrett Universal II (BUII) and the Barrett true axial length (BTAL). Other formulas were included: Cooke K6, EVO 2.0, and PEARL DGS.
The Barrett Universal II formula exhibited the most significant myopic mean prediction error at -0.15 ± 0.27 D, with the Cooke K6, PEARL-DGS, and EVO 2.0 formulas following. In terms of hyperopic mean prediction error, the PEARL-DGSsos formula recorded the highest value at 0.19 ± 0.32 D, succeeded by the EVO 2.0sos, Cooke K6sos, and BTAL formulas. The EVO 2.0, PEARL-DGS, Barrett Universal II, and Cooke K6 formulas demonstrated the lowest mean and median absolute errors, with BTAL, EVO 2.0sos, Cooke K6sos, and PEARL-DGSsos formulas trailing behind. The median absolute errors (MedAE) for EVO 2.0, PEARL-DGS, and Barrett Universal II were recorded at 0.13, 0.15, and 0.16 D, respectively.
BUII formula showed myopic shift with SOS biometry which increases with longer eyes. Using SOS option in Cooke K6, EVO 2.0, and PEARL-DGS formulas leads to a hyperopic shift in the mean prediction error which is undesirable. Using ALsos in those formulas without choosing the option of SOS yields a mean prediction error towards the myopic side which might be more desirable. All included formulas performed well with ALsos with most of the cases within + 1 D of intended refraction.
评估现代人工晶状体（IOL）屈光度计算公式中用于长眼的节段总和（SOS）生物测量法。
这是一项回顾性病例系列研究，纳入了177例患者的177只眼，眼轴长度（AL）≥24.5mm。术前使用ARGOS（爱尔康公司）测量眼轴长度。本研究使用了2种公式：巴雷特通用二代（BUII）和巴雷特真实眼轴长度（BTAL）。还纳入了其他公式：库克K6、EVO 2.0和PEARL DGS。
巴雷特通用二代公式表现出最显著的近视平均预测误差，为-0.15±0.27D，其次是库克K6、PEARL-DGS和EVO 2.0公式。就远视平均预测误差而言，PEARL-DGSsos公式记录的最高值为0.19±0.32D，其次是EVO 2.0sos、库克K6sos和BTAL公式。EVO 2.0、PEARL-DGS、巴雷特通用二代和库克K6公式显示出最低的平均和中位数绝对误差，BTAL、EVO 2.0sos、库克K6sos和PEARL-DGSsos公式紧随其后。EVO 2.0、PEARL-DGS和巴雷特通用二代的中位数绝对误差（MedAE）分别记录为0.13、0.15和0.16D。
BUII公式在SOS生物测量法中显示出近视偏移，且随着眼轴变长而增加。在库克K6、EVO 2.0和PEARL-DGS公式中使用SOS选项会导致平均预测误差出现远视偏移，这是不理想的。在那些公式中使用ALsos而不选择SOS选项会使平均预测误差向近视侧偏移，这可能更理想。所有纳入的公式在使用ALsos时表现良好，大多数病例的预期屈光在±1D范围内。
