Effects of orthokeratology on axial length growth in myopic anisometropes

Purpose: To investigate the effect of orthokeratology (ortho-k) lens wear on axial length (AL) growth in juvenile myopic anisometropes. Methods: This retrospective study consisted of two parts. In Part One, 25 anisometropic participants (mean age, 11.2 +/- 1.9 years; 11 females and 14 males) were fitted with ortho-k lenses in the more myopic eye only, and the rate of AL growth was compared between the ortho-k lens wearing eye and the untreated contralateral eye over an average period of 23.1 +/- 8.3 months. In Part Two, 8 participants who developed myopia in the contralateral eye received ortho-k treatment in both eyes for an average of 12 months; the rate of AL growth before and after ortho-k treatment in the newly developed myopic eye was compared. Results: In Part One, the rate of AL elongation in the ortho-k treated eye (0.08 +/- 0.15 mm/year) was significantly slower than in the contralateral eye (0.39 +/- 0.32 mm/year) (P < 0.001). At the completion of Part One, 16 out of 25 participants (64%) developed myopia in the initially non-myopic eye. In Part Two, the rate of AL elongation after ortho-k treatment in the newly developed myopic eye (0.20 mm/year) was significantly slower than that before ortho-k treatment in the same eye (0.49 mm/year) (P = 0.012). Conclusion: Ortho-k treatment slows AL growth in the more myopic eye of anisometropic patients; should the contralateral eye develop myopia in the future, ortho-k is capable of slowing down AL growth in that eye as well.