Toric Double Tear Reservoir Contact Lens in Orthokeratology for Astigmatism

Abstract

This study aimed at assessing the performance of a double tear reservoir toric reverse geometry contact lens design for the correction of myopic and astigmatic refractive errors through overnight orthokeratology (Ortho-K). Consecutive records of a total of 32 patients with refractive astigmatism greater than 1.25 D at any orientation, best corrected distance monocular visual acuity ≥ 1.00 (decimal) before Ortho-K treatment and stable ocular refraction for at least 1 month at the time of the last visit were retrospectively examined. Preorthokeratology and postorthokeratology information included noncycloplegic subjective refraction, best-corrected visual acuity, pupil diameter, corneal topography, and ocular aberrometry. The associations between the achieved myopic and cylinder reduction and the modifications in various corneal topographic parameters were investigated. Right eyes were chosen for data analysis. A statistically significant difference (Z=-4.805; P<0.001) was encountered between initial refractive sphere and final residual refractive sphere, with a dioptric change of -2.05 ± 1.46 D (median: -1.88; -5.25 to 0.50), accounting for a change of 106% of the initial myopia. Similarly, differences between pretreatment and posttreatment refractive cylinders were significant (Z=-4.945; P<0.001), with a dioptric change of -1.80 ± 1.06 D (median: -1.50; -5.25 to -0.50), that is, a change of 85% of the initial astigmatism. Changes in topographic Best Fit Sphere and Best Fit Toric presented a strong positive correlation with the accomplished myopic and astigmatic refractive changes, respectively. The results of this investigation suggest that the correction of astigmatic errors with toric orthokeratology lens designs may have a promising future.