Purpose To assess the repeatability and accuracy of optical biometry (Lenstar and IOLMaster) and ultrasound biometry (A-scan) in highly myopic eyes.
Design Comparative evaluation of diagnostic technology.
Participants Thirty-three subjects (66 eyes) with high myopia defined as spherical equivalent (SE) ≤ -6.00 D and axial length > 25.0 mm.
Methods Measurements of axial length (AL), anterior chamber depth (ACD) and average corneal radius of curvature (CR) obtained with the Lenstar were compared with those obtained with the IOLMaster and A-scan. Posterior staphyloma was identified by biomicroscopic fundus examination with a 78-D lens. Repeatability was evaluated with the coefficient of variation (CV). Agreement was evaluated using Bland-Altman analyses. The differences between three methods were assessed using the Friedman and Wilcoxon Signed-Rank tests, and their correlations were evaluated by Spearmans coefficient.
Main Outcome Measures AL, ACD, CR, central corneal thickness, lens thickness and white-to-white corneal diameter.
Results The mean SE of subjects was -11.1 ± 4.49 D with a range of -25.4 to -6.13 D. The CVs for repeated AL measurements using Lenstar, IOLMaster and A-scan were 0.05%, 0.07% and 0.2%, respectively. The limits of agreement (LoA) for AL were 0.12 mm between Lenstar and IOLMaster, 1.06 mm between Lenstar and A-scan, and 1.14 mm between IOLMaster and A-scan. The values for ACD were 0.28 mm, 0.51 mm and 0.52 mm, respectively. These repeatability and agreement results were comparable in extremely myopic (AL ≥ 27.0 mm) and staphylomatous eyes. Lenstar recorded similar values of CR compared to IOLMaster (7.66 ± 0.25 vs. 7.64 ± 0.24 mm), with an LoA of 0.12 mm.
Conclusions: Optical biometry provides more precise measurements of biometric parameters including AL, ACD and CR in highly myopic eyes compared to ultrasound biometry. |
