The Repeatability and Agreement of Ocular Parameters Measured with the MYAH and Myopia Master Devices between Expert and Non-Expert Practitioners

In myopia control, it is essential to measure the axial length (AL) and corneal parameters, and to monitor whether changes in these parameters have occurred over time. The aim of this study was to analyse the repeatability and agreement between expert and non-expert practitioners in ocular parameters measured by the MYAH and Myopia Master. Three repeated measurements (n = 42) were recorded with the MYAH and Myopia Master by two (an expert and a non-expert) observers in a randomized order. The AL, K1, K2, and white-to-white (WTW) distance were collected. The intraobserver repeatability was excellent in all parameters measured with both devices in both observers. The AL outcome presented the best repeatability with the MYAH and Myopia Master (intraclass correlation coefficient, ICC = 1.0; coefficient of variation, CV <= 0.06% for both observers), while the WTW presented poorer results (ICC <= 0.991; CV <= 0.52%). The Myopia Master provides a significantly (p <= 0.01) flatter K1 and K2 as well as a lower WTW (p <= 0.01) than the MYAH. No statistically significant difference in AL measurements was found with either device (p >= 0.10; ICC = 1.0). None of the parameters showed differences (p >= 0.12) between the expert and non-expert observer. The MYAH and Myopia Master provide consistent measurements in a healthy adult population regardless of the previous clinical experience of the observer. AL measurements should be used interchangeably but K1, K2, and WTW should be used interchangeably with caution.