Fig. 2

Axial elongation in one year based on the usage of different back optic zone diameter (BOZD). a The alterations in axial length (AL) within the 5-mm back optic zone diameter (BOZD) group were measured as 0.07 ± 0.15 mm during the 6-month examination and 0.13 ± 0.18 mm during the 12-month examination. These changes were comparatively lesser than those observed in the 6-mm BOZD group, which were recorded as 0.14 ± 0.13 mm during the 6-month visit and 0.27 ± 0.15 mm during the 12-month visit. (6-mm, 5-mm: the BOZD of the orthokeratology lenses measuring 6 mm and 5 mm, respectively; data are expressed as mean ± SD; repeated measures ANOVA, ^***P < 0.001). b The occurrence rates of axial growth measurements falling below 0 mm, ranging between 0 and 0.2 mm, and exceeding 0.2 mm, in relation to various BOZDs of orthokeratology