Effects of orthokeratology on corneal reshaping and the delaying of axial eye growth in children.

Purpose: To investigate the inhibition of myopia progression and axial elongation in children wearing orthokeratology (OK) lenses, as well as to evaluate the status of corneal reshaping, this study explores the relationship between changes in central corneal curvature (K-value) and e-value induced by OK lenses and axial elongation.

Methods: In this study, it is planned to select children aged 8-15 who wear orthokeratology lenses at the Pediatric Ophthalmology and Strabismus Clinic of the Second Affiliated Hospital of Dalian Medical University. All children will undergo slit lamp examination, visual acuity assessment, computerized refraction, intraocular pressure measurement, biometry, and corneal topography examination before lens wear and at 1 month, 3 months, and 6 months after lens wear in the pediatric ophthalmology clinic. Based on age (lower age group (8 < age ≤12 years); higher age group (12 < age ≤15 years)) and baseline equivalent spherical (SE) value (mild myopia group (-1.00 D < SE ≤ -3.25D); moderate myopia group (-3.25 D < SE ≤ -6.00 D)), four groups will be formed by pairing these factors. Suitable data will be selected according to inclusion and exclusion criteria, and different groups will be included. Data will be organized, and statistical analysis will be performed using SPSS software to obtain the results. The expected results will be discussed and analyzed.

Results: After wearing OK lenses, all four groups achieved good visual acuity at follow-up. At 6 months, there were no significant differences in visual acuity among the four groups ( = 0.149, >0.05). There were no significant differences in refractive error among the four groups ( = 0.066, >0.05). Baseline axial length differed significantly among the four groups ( = 0.000, <0.001), with the LM group having longer axial length than the LL group (P < 0.001, paired samples -test), and the HM group having longer axial length than the HL group ( < 0.001, paired samples -test). However, there were no significant differences in axial length change compared to baseline among the groups at 1 month, 3 months, and 6 months (  = 0.053;  = 0.557;  = 0.329, >0.05). Significant differences were observed in corneal flat K-value change compared to baseline among the four groups at 1 month, 3 months, and 6 months (  = 0.001,  = 0.001,  = 0.004, <0.05). There were no significant differences in e-value change among the groups at 1 and 3 months (  = 0.205,  = 0.252, >0.05), but significant differences were found in e-value change compared to baseline at 6 months (  = 0.010, <0.05). Multiple regression analysis with changes in central corneal flat K-value and e-value as independent variables and axial elongation as the dependent variable showed a correlation between e-value change at 6 months and axial elongation ( = 0.004, <0.05), indicating a negative correlation.

Conclusion: Orthokeratology (OK) lenses effectively improve myopic children's vision by reshaping the cornea, leading to reduced central corneal curvature and flattening of its anterior surface. The effectiveness of OK lenses is not significantly affected by age or initial myopia severity. Children of varying ages and myopia levels experience similar levels of axial length control with OK lens wear. Changes in corneal shape due to OK lenses affect axial elongation, with greater changes in corneal morphology associated with smaller increases in axial length.