Effect of Toric Orthokeratology Lenses in Patients with Limbus to Limbus Corneal Astigmatism

ABSTRACT

PURPOSE: To report the efficacy of toric orthokeratology lenses in patients with astigmatism within 1.5 D having difficulty in wearing spherical orthokeratology lenses due to the limbus-to-limbus corneal astigmatism. METHODS: Twenty-three eyes of 16 patients with limbus-to-limbus corneal astigmatism who had been wearing toric orthokeratology lenses for more than 6 months were recruited. The uncorrected visual acuity (UCVA), refractive error, and keratometric changes including eccentricity before and after wearing lenses were compared, and the correlations between corneal astigmatism as well as refractive astigmatism and lens toricity were assessed. RESULTS: After wearing the lens, UCVA (log MAR) significantly improved from 0.61 +/- 0.22 to 0.05 +/- 0.08 (p < 0.001). Myopia and spherical equivalent were also reduced significantly (p < 0.001 and p < 0.001, respectively). While Simulated K (Sim K) tended to be more flattened (p < 0.001) and the eccentricity showed significant decrease (p < 0.001), corneal and refractive astigmatism were not changed significantly (p = 0.330 and p = 0.124, respectively). Correlations between corneal and refractive astigmatism and lens toricity were not statistically significant (r = 0.244, p = 0.300; r = -0.051, p = 0.832). No patients showed lens decentration or visual discomfort. CONCLUSIONS: Corneal topography was essential in patients who had difficulty in wearing spherical orthokeratology lenses due to the limbus-to-limbus corneal astigmatism. Toric orthokeratology lenses may be an effective treatment option in patients with limbus-to-limbus corneal astigmatism.