Abstract：Objective To explore the relationship between the average height difference between flattening central cornea and relatively steepening mid-peripheral cornea (AHDCAP) on axial length (AL) after wearing orthokeratology lenses and to analyze the correlation between AHDCAP and myopia progression. Methods A retrospective study was conducted on 300 patients (300 eyes) diagnosed with myopia and wearing orthokeratology lenses at Aier Eye Hospital from January 2018 to January 2020. They were divided into 3 groups according to age: 8-9 years old, 10-12 years old and 13-15 years old, and into 3 groups according to the equivalent spherical refraction: -1.00 D- -2.00 D, -2.25 D- -4.00 D and -4.25 D- -6.00 D. The growth of AL and the relationship between AHDCAP and AL after wearing orthokeratology lenses were analyzed in different age groups and different myopia degrees. Results The increases of AL in different age groups were 0.31 (0.20, 0.43)mm, 0.18(0.07,0.30)mm and 0.12(0.04, 0.24)mm, respectively, with significant differences among the three groups (χ2=48.36, P<0.001). After 1 year of wearing orthokeratology lenses in different myopia groups, the increase of AL was 0.32(0.15, 0.43) mm, 0.24(0.11,0.32)mm and 0.13(0.04,0.23)mm, respectively, with significant differences among the three groups (χ2=36.95, P<0.001). The AHDCAP values of different myopia groups after wearing orthokeratology lenses for 1 year were 12.25(8.25, 17.75) μm, 12.88(10.69, 19.38) μm and 20.75(13.94,24.09) μm , respectively, with significant differences among the three groups (χ2=57.50, P<0.001).AHDCAP was negatively correlated with both equivalent spherical lens (r=-0.394,P=0.000) and AL growth (r=-0.829,P=0.001). Conclusions The smaller the AHDCAP, the faster the AL growth and myopia development after wearing orthokeratology lenses. On the contrary, the larger the AHDCAP, the slower the AL growth and myopia development. Increasing AHDCAP is beneficial to control AL growth in myopic children.
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2024, Vol. 35 
