title: Myopia control using toric orthokeratology (TO-SEE study).
abstract: OBJECTIVE
  This nonrandomized clinical study aimed to investigate the effectiveness of toric orthokeratology (ortho-k) for myopia control in myopic children with moderate-to-high astigmatism
  
  
  METHODS
  We enrolled 80 subjects (aged 6-12 years; ortho-k, 43; control, 37) with myopia of 0.50 to 5.00 diopters (D), and with-the-rule astigmatism of -1.25 to -3.50 D, and unremarkable ocular and general conditions. Data collection, including visual acuity, subjective and objective refraction, axial length, corneal topography, and biomicroscopy examination, was performed every 6 months during the 24-month study period. Results from the right eye or the eye with higher astigmatism were reported.
  
  
  RESULTS
  A total of 35 ortho-k and 23 control subjects completed the study successfully. Subjects in both groups demonstrated axial elongation (P < 0.001). The average axial elongation at the end of study was 0.31 ± 0.27 and 0.64 ± 0.31 mm in the ortho-k and control groups, respectively (P < 0.001). At the end of 24 months, axial elongation in ortho-k subjects was 52% slower than that in the control group. Axial elongation was correlated significantly with the initial age of the subjects (P = 0.02) and treatment assigned (P = 0.04), but not with sex, initial myopia, initial refractive cylinder, or initial corneal toricity (P > 0.08).
  
  
  CONCLUSIONS
  Toric ortho-k lenses can slow axial elongation effectively in myopic children with moderate-to-high astigmatism. (ClinicalTrials.gov number, NCT00978692.).
authors.affiliation: The Hong Kong Polytechnic University, School of Optometry, Hung Hom, Kowloon, Hong Kong, China.
authors.forename: Connie
authors.initials: C
authors.lastname: Chen
authors.forename: Sin Wan
authors.initials: SW
authors.lastname: Cheung
authors.forename: Pauline
authors.initials: P
authors.lastname: Cho
mesh_terms: D001251:Astigmatism / Q000150:complications / Q000503:physiopathology / Q000628:therapy; D002648:Child; D003261:Contact Lenses; D003315:Cornea / Q000473:pathology* / Q000503:physiopathology; D019781:Corneal Topography; D004867:Equipment Design; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D009216:Myopia / Q000150:complications / Q000503:physiopathology / Q000628:therapy*; D054158:Orthokeratologic Procedures / Q000379:methods*; D012029:Refraction, Ocular / Q000502:physiology*; D016896:Treatment Outcome; D014792:Visual Acuity
keywords: astigmatism; myopia; myopia control; orthokeratology; toric design