Fig. 1

Methods to determine the treatment zone size, the treatment zone decentration and the RCRP for OK wearers. a Tangential curvature map at baseline; b Tangential curvature map at the 12-month visit; c Difference map used to determine the treatment zone size and decentration. The red circle represents the boundary of the treatment zone. The red cross indicates the center of the circle, and R is the circle radius used for calculating treatment zone diameter. The white cross represents the corneal apex, and r represents the distance of treatment zone decentration. d Axial power map at baseline; e Axial power map at the 12-month visit; f The RCRP map; g Representative examples from individual participants of mean RCRP profiles within the average pupillary diameter (4.80 mm) in the 5.0 mm-BOZD OK group and 6.2 mm-BOZD OK group. BOZD, back optic zone diameter; OK, orthokeratology; RCRP, relative corneal refractive power