Difference and consistency analysis of the parameters for intraocular lens calculation measured by Pentacam AXL and Lenstar LS900

Objective

To evaluate the precision of Pentacam AXL in measuring the parameters required for intraocular lens (IOL) calculation and compare the results with those obtained with Lenstar LS900.

Methods

A cross-sectional study was designed.Seventy patients (91 eyes) with age-related cataract treated in Xiamen Eye Center Affiliated to Xiamen University from March to August, 2017 to receive cataract surgery were collected.Biometry measurements in 91 eyes of 70 cataract patients were performed by the same examiner with Pentacam AXL and Lenstar LS900 before surgery.The axial length (AL), keratometry (K) and anterior chamber depth (ACD) were obtained.The differences between the two devices were analyzed by paired-samples t test and Pearson correlation analysis.Differences and correlation of biometry measurements obtained with two biometers were analyzed.The agreement of the two biometers was analyzed by Bland-Altman plot.Written informed consent was obtained from each subject prior to entering the study cohort.The study protocol was approved by the Ethics Committee of Xiamen Eye Center Affiliated to Xiamen University (No.XMYKZX-LW-2017-003).

Results

The mean values of AL were (23.39±1.34)mm and (23.42±1.36)mm, mean keratometry (Km) values were (43.96±1.53)D and (44.00±1.51)D, respectively, and the ACD values were (2.89±0.38)mm and (2.88±0.37)mm respectively measured by Pentacam AXL and Lenstar LS900, and the differences were not statistically significant (P= 0.906, 0.855, 0.811), but all of the three biometrey measurements showed good linear correlation (r = 0.999, 0.975, 0.991; all at P<0.05). AL, Km and ACD between Pentacam AXL and Lenstar LS900 showed good agreements analyzed by Bland-Altman plot, and the respective 95% limits of agreement (95%LoA) for AL and ACD were -0.11 to 0.07 mm and -0.09 to 0.12 mm, while 95% LoA for Km was -0.70 to 0.62 D.

Conclusions

Pentacam AXL can provide accurate parameters for IOL calculation, which has a good agreement with Lenstar LS900, and the AL and ACD parameters can be used interchangeably.