Short-Term and Long-Term Changes in Corneal Power Are Not Correlated With Axial Elongation of the Eye Induced by Orthokeratology in Children

Purpose: To assess the relationship between short-term and long-term changes in power at different corneal locations relative to the change in central corneal power and the 2-year change in axial elongation relative to baseline in children fitted with orthokeratology contact lenses (OK). Methods: Thirty-one white European subjects 6 to 12 years of age and with myopia -0.75 to -4.00 DS and astigmatism <= 1.00 DC were fitted with OK. Differences in refractive power 3 and 24 months post-OK in comparison with baseline and relative to the change in central corneal power were determined from corneal topography data in eight different corneal regions (i.e., N[nasal] 1, N2, T[temporal]1, T2, I[inferior]1, 12, S[superior]1, S2), and correlated with OK-induced axial length changes at two years relative to baseline. Results: After 2 years of OK lens wear, axial length increased by 0.48 +/- 0.18 mm (P<0.001), which corresponded to an increase of 1.94 +/- 0.74% ([2-years change in axial length/baseline axial length]x100). However, the change in axial elongation in comparison with baseline was not significantly correlated with changes in corneal power induced by OK relative to baseline for any of the corneal regions assessed (all P>0.05). Conclusion: The reduction in central corneal power and relative increase in paracentral and pericentral power induced by OK over 2 years were not significantly correlated with concurrent changes in axial length of white European children.