Residual Corneal Flattening After Discontinuation of Long-Term Orthokeratology Lens Wear in Asian Children

Abstract

Most patients treated with orthokeratology (OK) in Asia are children. The effects of long-term OK on corneal curvature among children after lens wear discontinuation have not previously been reported. This study investigated 28 subjects, aged 10.4 +/- 2.5 years at commencement of OK lens wear, who had been treated with OK for 50.2 +/- 27.4 months. Corneal curvature was measured with a Canon RK3 autokeratometer before commencement of OK and again approximately 2 weeks (17.3 +/- 8.6 days) after discontinuation of OK lens wear. Data were analyzed using paired Student t tests, with a critical P value of 0.05. Compared with baseline, residual flattening of the cornea was found after cessation of OK lens wear, averaging 0.07 +/- 0.04 mm in the flat meridian (P<0.001) and 0.02 +/- 0.07 mm in the steep meridian (P=0.07). This was confirmed by power vector analysis of curvature data, with a significant reduction in M (-0.27 +/- 0.23 diopter (D); P<0.001), and a slight increase in J0 (0.17D +/- 0.36D; P=0.02). A trend toward greater residual corneal flattening was found among subjects with more pretreatment myopic refractive error (P=0.04). Corneal curvature may not necessarily return completely to baseline after discontinuation of long-term OK lens wear in children. Intermittent temporary discontinuation of OK lens wear and close monitoring of corneal recovery are recommended during long-term OK treatment.