Comparison of intraocular lens power calculation using a standard ultrasonic biometer and a new optical biometer

Abstract

AIM:To compare the intraocular lens (IOL) power calculations and refractive outcomes obtained with a new optical biometer and standard ultrasonic biometer in phacoemulsification surgery. METHODS:Thirty-seven eyes of 37 cataract patients who underwent phacoemulsification with IOL implantation were included in this prospective comparative study. The same operator performed biometer measurements in eyes with cataract using a new optical biometer (Aladdin) and a standard ultrasonic biometer (Sonomed AB 5500). Biometric parameters; axial length (AL), keratometric (K) readings, anterior chamber depth (ACD) and IOL power obtained by two devices were recorded. Postoperative actual refractive errors and errors predicted by two devices according to SRK/T formula were analyzed. The mean estimation error (EE), mean absolute estimation error (AEE) and the biometric parameters obtained by two biometers were compared. RESULTS:The AL measured by Aladdin (23.45±0.73 mm) was significantly longer than AL by ultrasonic biometer (23.2±0.75 mm) (P=0.01). The mean EE and AEE values obtained by Aladdin were significantly smaller than the values by ultrasonic biometer (P=0.0006 and 0.03 respectively). The higher percentage of eyes within ±0.5 and ±1.00 D of target refraction was also found by using Aladdin (67% and 97%). CONCLUSION:The Aladdin optical biometer showed better accuracy and yielded better refractive outcomes compared with ultrasonic biometer.

目的：比较超乳手术时应用新型光学生物测量仪和标准超声波测量仪计算人工晶状体的屈光度及屈光结果。 方法:前瞻性研究。研究包含37例37眼白内障患者接受白内障超声乳化联合人工晶状体植入术。同一测量人员分别使用新型光学生物测量仪(Aladdin)与标准超声波测量仪(Sonomed AB 5500)对白内障患者进行检测。通过这两种设备记录生物测定参数，包括眼轴长度、角膜曲率、前房深度及人工晶状体屈光度数。分析术后实际屈光不正与两台设备根据SRK/T公式计算的误差，比较两台设备检查结果的平均估计误差(EE)、平均绝对估计误差(AEE)及生物测定参数。 结果:Aladdin测量仪(23.45±0.73 mm)较超声波测量仪(23.2±0.75 mm)检测出的眼轴显著较长(P=0.01)。Aladdin测量仪的EE与AEE均明显小于超声波测量仪(P=0.0006与0.03)。应用Aladdin测量的大多数眼与目标屈光度相差在±0.5(67%)及±1.00(97%)以内。 结论:Aladdin光学生物测量仪较超声波测量仪更精确，屈光结果更准确。