title: Residual corneal flattening after discontinuation of long-term orthokeratology lens wear in asian children.
abstract: OBJECTIVE
  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.
  
  
  METHODS
  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.
  
  
  RESULTS
  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).
  
  
  CONCLUSIONS
  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.
authors.affiliation: University of New South Wales, Sydney, Australia.
authors.forename: Richard
authors.initials: R
authors.lastname: Wu
authors.forename: Fiona
authors.initials: F
authors.lastname: Stapleton
authors.forename: Helen A
authors.initials: HA
authors.lastname: Swarbrick
mesh_terms: D000293:Adolescent; D044466:Asian People; D002648:Child; D003315:Cornea / Q000473:pathology*; D019781:Corneal Topography; D006801:Humans; D009216:Myopia / Q000208:ethnology / Q000473:pathology* / Q000503:physiopathology / Q000628:therapy*; D054158:Orthokeratologic Procedures; D012029:Refraction, Ocular; D013997:Time Factors