Comparison of Refraction Obtained with the Myopia Master and Subjective Manifest Refraction in Pediatric Orthokeratology.

Background: Objective refraction plays an increasingly important role in paediatric myopia control. However, evidence regarding its agreement with subjective refraction in children undergoing orthokeratology (OK), particularly under non-cycloplegic conditions, remains limited. This study evaluated the longitudinal agreement between Myopia Master refraction obtained with the device and subjective manifest refraction during the first six months of OK treatment. Methods: A prospective longitudinal study included children aged 8-12 years fitted with OK lenses featuring a customized optical treatment zone. Subjective manifest refraction and Myopia Master refraction using the Myopia Master® were performed at baseline and after 3 and 6 months under physiological pupillary conditions without cycloplegia. Agreement was assessed using paired comparisons, intraclass correlation coefficients (ICC), and Bland-Altman analysis. Results: Forty-three myopic participants were included at baseline. Excellent agreement was observed for sphere, spherical equivalent (M), and overall blur strength (B) (ICC ≥ 0.937), whereas cylinder and J45 showed lower agreement (ICC ≥ 0.701). Agreement decreased after OK treatment, particularly at 3 and 6 months. Bland-Altman analysis showed small mean bias with wider limits of agreement during follow-up. Conclusions: The Myopia Master® showed clinically useful agreement for most subjects with subjective manifest refraction throughout the first six months of paediatric OK treatment. Despite reduced agreement after treatment initiation due to corneal remodelling, Myopia Master refraction remained a valuable complementary tool for routine follow-up under physiological pupillary conditions.