Inter-Examiner and Inter-Instrument Agreement of the Myopia Master with the IOL Master 700 and NVisionK 5001 in...

Background/Objectives: The measurement of axial length (AL) is important to monitor the success of interventions to slow childhood myopia, but traditional biometers are expensive for clinicians to acquire. To address this, Oculus has developed the Myopia Master (MM), which measures auto-refraction (AR), corneal curvature (CC) and AL. This study compared inter-instrument and inter-examiner measures on the MM, IOL Master 700 (Carl Zeiss Meditec, Jena, Germany) and NVisionK-5001 (Shin-Nippon, Tokyo, Japan) in myopic children. Methods: Fifty-six myopic children participated (mean age 11.93 ± 1.93 years). A first examiner obtained the following under cycloplegia: (i) AR using the NVisionK, (ii) AL and CC using the IOL Master 700 and (iii) AR, AL and CC using the MM. The latter measures were repeated by a second examiner to assess inter-examiner agreement of the MM. Mean differences (MD) and 95% limits of agreement (LoA) were calculated. Spherical equivalent refraction (SER) was calculated using AR values. Acceptable LoA for AL, SER and CC were defined as ±0.05 mm, ±0.40 D and ±0.06 mm, respectively. Results: Inter-instrument LoA between the MM and IOL Master 700 for AL and CC were acceptable (MD 0.02 mm; 95%LoA -0.02 to 0.06 mm and MD 0.025 mm, 95% LoA -0.03 to 0.08 mm, respectively). SER measures between the NVisionK-5001 and MM were not acceptable (MD -0.44 D, 95% LoA -0.91 to 0.03 D). SER values were, on average, 0.44 D more negative when using the MM. Inter-examiner measures on the MM were all acceptable (AL MD 0.00 mm; 95% LoA -0.04 to 0.04 mm; SER MD -0.01 D; 95% LoA -0.33 to 0.32 D; CC MD 0.01 mm; 95% LoA -0.03 to 0.05 mm). Conclusions: The MM demonstrated excellent inter-examiner repeatability. Inter-instrument agreement between the MM and IOL Master 700 for the AL and CC measures showed excellent agreement. The MM over-estimated myopia SER compared with the NVisionK-5001.