Effect of orthokeratology on anisometropia control: A meta-analysis

Abstract

Background: The effectiveness of orthokeratology in retarding anisometropic progression has been investigated in several small-sample studies. This quantitative analysis aimed to elucidate the efficacy of orthokeratology for anisometropia control. Methods: We searched PubMed, Embase, and Cochrane databases for relevant studies through September 2020. Axial length (AL) data at baseline and final follow-up were extracted, and AL elongation and difference were calculated. Methodological quality was evaluated using the risk of bias in non-randomized studies of interventions (ROBINS-I) tool. Meta-analyses were performed using a fixed-effect model based on the heterogeneity. Results: A total of 10 cohort studies (nine retrospective studies; one prospective study) were included. The pooled results for the unilateral myopia group showed that the mean AL elongation difference between myopic and emmetropic eyes was −0.27 mm (95% CI, −0.31 to −0.22; p < 0.01) at the one-year follow-up (four studies) and −0.17 mm (95% CI, −0.33 to −0.02; p = 0.03) at the two-year follow-up (two studies). In the bilateral anisomyopic group, mean AL elongation difference between high and low myopic eyes was −0.06 mm (95% CI, −0.09 to −0.04; p < 0.01) at the one-year follow-up (seven studies) and −0.13 mm (95% CI, −0.21 to −0.06; p < 0.01) at the two-year followup (three studies). Conclusion: This study demonstrated that orthokeratology can effectively retard myopic progression and reduce anisomyopic values. However, additional wellstructured randomized controlled trials or prospective studies with longer follow-up periods are warranted to address this topic in more detail.

Keywords

• Anisometropia
• Anisomyopia
• Axial length
• Orthokeratology
• Ortho-K lens
• Unilateral myopia