Comparison of Three Different Devices for the Evaluation of Axial Length, Refractive Error, and Keratometry

Myopia prevalence is increasing worldwide. Axial length, refractive error, and keratometry are important outcome measures in myopia management. Precise measurement methods are required for myopia management. Various devices are used to measure these three parameters, and it is not known whether their results can be used interchangeably.

The aim of this study was to compare three different devices to evaluate axial length, refractive error, and keratometry.

A total of 120 subjects (37.7 ± 15.5 years) were enrolled in this prospective study. All subjects were measured with DNEye Scanner 2 (Rodenstock GmbH, Munich, Germany), Myopia Master (Oculus Optikgeräte GmbH, Wetzlar, Germany), and IOLMaster 700 (Carl Zeiss Meditec AG, Jena, Germany). Myopia Master and IOLMaster 700 use interferometry to measure axial length. Rodenstock Consulting software (Rodenstock GmbH, Munich, Germany) was used to calculate axial length from DNEye Scanner 2 measurement. Differences were analyzed using Bland-Altman 95% limits of agreement.

Differences for axial length were as follows: DNEye Scanner 2 versus Myopia Master, 0.67 ± 0.46 mm; DNEye Scanner 2 versus IOLMaster 700, 0.64 ± 0.46 mm; and Myopia Master versus IOLMaster 700, -0.02 ± 0.02 mm. Differences for mean corneal curvature were as follows: DNEye Scanner 2 versus Myopia Master, -0.20 ± 0.36 mm; DNEye Scanner 2 versus IOLMaster 700, -0.40 ± 0.35 mm; and Myopia Master versus IOLMaster 700, -0.20 ± 0.13 mm. The difference in noncycloplegic spherical equivalent between DNEye Scanner 2 and Myopia Master was 0.05 ± 0.25 D.

The results for axial length and keratometry from Myopia Master and IOLMaster were comparable. The axial length calculated by DNEye Scanner 2 was significantly different from interferometry devices and is not appropriate for myopia management. The differences in keratometry readings were clinically not significant. All refractive outcomes were comparable.