AIM: To investigate the alterations in corneal aberration and relative refractive power following the reduction of back optic zone diameters(BOZD)of orthokeratology lenses.

METHODS: Myopic children aged 8-12 years, deemed suitable and willing to wear orthokeratology lenses, were randomly allocated to wear lenses with a 6.0 mm BOZD or a 5.0 mm BOZD. Data collection included changes in higher-order aberrations, relative refractive power and the treatment zone diameter of the two groups after wearing lenses for 1 d, 1 wk, 1, and 3 mo. The correlation of increase in corneal higher-order aberrations with refractive power was analyzed.

RESULTS: The increases in total higher-order aberrations, spherical aberrations and coma aberrations varied over time following lens wear(all P<0.001), and there were no statistically significant differences in the changes of total higher-order aberrations and coma aberrations between the two groups of patients(all P>0.05). A significant difference was observed in the increment of spherical aberrations in the 5 mm range between the two groups of patients, which varied over time(F_time=40.179, P_time<0.001; F_group=11.948, P_group=0.001; F_interaction=3.262, P_interaction=0.03). A significant difference was observed in the increment of spherical aberrations in the 4 mm range between the two patient groups(F_time=34.462, P_time<0.001; F_group=13.094, P_group<0.001; F_interaction=1.372, P_interaction=0.25). There was no statistically significant distinction in relative refractive power between the two groups(F_group=0.048, P_group=0.83; F_interaction=1.208, P_interaction=0.31); however, relative refractive power changed over time(F_time=40.030, P_time<0.001). The difference in treatment zone diameter between the two groups was statistically significant, with changes over time(F_time=11.212, P_time<0.001; F_group=74.073, P_group<0.001; F_interaction=0.312, P_interaction=0.82). The total higher-order aberrations, spherical aberrations, and coma aberrations in 4, 5 and 6 mm range showed a positive correlation with relative refractive power values(all P<0.001). Statistically significant difference was observed in the axial length between the two groups after wearing lenses for 3, 6 and 12 mo(F_time=185.398, P_time<0.001; F_group=5.618, P_group=0.02; F_interaction=2.315, P_interaction=0.11).

CONCLUSION: Orthokeratology lenses leaded to elevated higher-order aberrations. Orthokeratology lenses with smaller BOZD produced significantly greater spherical aberrations at 4 and 5 mm range and smaller treatment zone diameters. The corneal total higher-order aberration was positively correlated with relative refractive power. Wearing orthokeratology lenses with a smaller BOZD can cause slower axial growth and better myopia control.