title: High myopia-partial reduction orthokeratology (HM-PRO): study design.
abstract: OBJECTIVE
  To report the study design and preliminary results of a pilot study, High Myopia-Partial Reduction Orthokeratology study.
  
  
  METHODS
  Children with myopia of 6.00D or above and who satisfied the recruitment criteria were randomly assigned to partial reduction orthokeratology (PR ortho-k) and spectacle-wearing control groups. The myopia of the PR ortho-k children were partially reduced using custom made 4-zone ortho-k lenses of target 4.00D. Residual refractive errors were corrected with single vision spectacles. Control subjects were fully corrected with single vision spectacles. PR ortho-k subjects were also required to return for assessment after the first overnight lens wear, and one week and one month after lens wear.
  
  
  RESULTS
  Fifty-two eligible subjects were randomly assigned to PR ortho-k group (n=26) and control group (n=26). The median age of each group was 10.00 years. The median (range) subjective myopia of the right eye at baseline was 6.41D (5.00-8.00D) and 6.22D (6.00-8.00D) for PR ortho-k and spectacle groups, respectively (p>0.05). Nineteen (79%) PR ortho-k subjects achieved successful lens fit at the one month visit and the median myopic reduction was 3.75D in the right eye. The incidence of (mild) corneal staining in PR ortho-k subjects reduced from 30% at the first overnight lens wear to 16% at the 1-month visit. Corneal pigmented arc was observed in 32% of PR ortho-k subjects at the 1-month visit.
  
  
  CONCLUSIONS
  PR ortho-k was successfully applied to high myopic children with no significant changes in ocular health/best corrected visual acuity after one month of lens wear.
authors.affiliation: School of Optometry, The Hong Kong Polytechnic University, Hong Kong. jessie@eyecare.com.hk
authors.forename: Jessie
authors.initials: J
authors.lastname: Charm
authors.forename: Pauline
authors.initials: P
authors.lastname: Cho
mesh_terms: D002648:Child; D003261:Contact Lenses; D005139:Eyeglasses; D005260:Female; D006801:Humans; D008297:Male; D009216:Myopia / Q000175:diagnosis* / Q000534:rehabilitation*; D054158:Orthokeratologic Procedures / Q000295:instrumentation* / Q000379:methods*; D010865:Pilot Projects; D012107:Research Design; D016037:Single-Blind Method; D016896:Treatment Outcome