Effect of orthokeratology in patients with myopic regression after refractive surgery

Purpose: To evaluate the clinical effect of orthokeratology (ortho-K) lenses and to introduce the fitting steps of ortho-K lens for myopic regression after keratorefractive surgery. Methods: Twenty-one eyes from 12 patients with myopic regression after keratorefractive surgery were fitted with ortho-K lenses and followed up for 12.11 +/- 3.68 months. The mean K value of the peripheral cornea was used to speculate preoperative central corneal K value, estimated K. After dispensing the lenses according to estimated K, biomicroscopic examination including fluorescein staining and over refraction were performed to determine the final K and final lens power. Results: LogMAR uncorrected visual acuity was 0.48 +/- 0.39 before and 0.00 +/- 0.00 after wearing ortho-K lenses (p < 0.001). Pre-fitted refractive error was -1.87 +/- 1.05 diopters (D) in myopia, 0.54 +/- 0.42 D in astigmatism, and spherical equivalent of 2.14 +/- 1.01 D. At the final visit myopia level and spherical equivalent significantly decreased to -0.73 +/- 0.84 D (p < 0.001) and -1.01 +/- 0.87 D (p < 0.001), respectively. Estimated K was 8.07 +/- 0.36 mm, and final K used for ortho-K prescription was 8.19 +/- 0.30 mm. Final K significantly correlated with K value of pre-fitted peripheral cornea (r = 0.737, p < 0.001) and estimated K (r=0.721, p < 0.001), respectively. There was no correlation between pre-fitted degree of myopia and the Final lens power (r = 0.429, p = 0.053). Conclusions: Ortho-K lenses may be an effective solution for patients with myopic regression following keratorefractive surgery. Estimated K value can be used as reference value in ortho-K prescription. (C) 2015 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.