Abstract
OBJECTIVES: To evaluate the impact of a new orthokeratology (OrthoK) lens on corneal epithelial thickness and higher-order aberrations (HOAs). METHODS: This three-arm, prospective, crossover study randomly assigned participants to the control group, T1 group (1.5× control-group lens-design reverse curve [RC] height), and T2 group (2× control-group lens-design RC height). Participants underwent basic ophthalmological examinations, corneal topography, and corneal epithelial thickness and HOA measurements at each visit. Corneal zones were analyzed based on topographic changes induced by lens wear, corresponding to the central treatment zone and the reverse zone. RESULTS: The spherical equivalent was significantly lower in T1 and T2 than in the control group on days 7 and 28 of lens wear ( P <0.001). The corneal curvature was noticeably flatter in T1 and T2 than in the control group. No significant differences were observed among groups in the epithelial thickness of the central treatment zone after OrthoK lens wear. However, epithelial thickness in the reverse zone was significantly greater ( P <0.05) in T1 and T2 compared with the control group after 28 days of lens wear. A significant difference in HOA was observed among the three groups after OrthoK lens wear for 1 and 7 days ( P <0.01). T2 demonstrated higher levels of HOA than the other groups. CONCLUSIONS: This new design of OrthoK can alter the corneal epithelium thickness and stabilize central corneal flattening, thereby achieving a better correction for myopia. However, this design also induces HOAs and is associated with a mild but significant compromise in uncorrected visual acuity compared with conventional designs. Therefore, clinicians should weigh the potential benefits of myopia control against the associated effects on visual quality when selecting OrthoK lens designs.