High Myopia-Partial Reduction Ortho-K: A 2-year Randomized Study

Optom Vis Sci. 2013 Jun;90(6):530-9. doi: 10.1097/OPX.0b013e318293657d.

Abstract

Purpose: To investigate if the combination of partial reduction (PR) orthokeratology (ortho-k) and spectacles for residual refractive errors in the daytime was effective to slow myopic progression in high myopic children.

Methods: High myopic children (aged 8 to 11 years) with spherical equivalent refraction at least -5.75 diopters (D) and myopia -5.00 D or more myopic were recruited and randomly assigned into PR ortho-k and control groups. Subjects in the PR ortho-k group were fitted with custom made four-zone ortho-k lenses with target reduction of 4.00 D for both eyes, and the residual refractive errors were corrected with single-vision spectacles for clear vision in the daytime. Control subjects were fully corrected with single-vision spectacles. Axial length of each eye of all subjects was measured with the IOLMaster at 6-month intervals by a masked examiner. This study was registered at www.clinicaltrial.gov with the identifier NCT00977236.

Results: Fifty-two subjects were recruited and randomized to the PR ortho-k and control groups. Twelve PR ortho-k and 16 control subjects completed the study. Compared with the residual refractive errors at the 1-month visit (after stabilization of ortho-k treatment), the median increase in noncycloplegic residual myopia at the 24-month visit was 0.13 D. In the control group, the median increase in myopia was 1.00 D at the end of the study. The mean ± SD increases in axial length were 0.19 ± 0.21 mm in the PR ortho-k group and 0.51 ± 0.32 mm in the control group (95% confidence interval, -0.55 to -0.12; unpaired t test, p = 0.005).

Conclusions: This single-masked randomized study showed that PR ortho-k effectively slowed myopic progression in high myopes. Axial length elongation was 63% slower in PR ortho-k-treated children compared with children wearing spectacles.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Axial Length, Eye
  • Child
  • Corneal Topography
  • Disease Progression
  • Eyeglasses*
  • Female
  • Humans
  • Male
  • Myopia, Degenerative / diagnosis
  • Myopia, Degenerative / physiopathology
  • Myopia, Degenerative / therapy*
  • Orthokeratologic Procedures*
  • Refraction, Ocular / physiology
  • Single-Blind Method
  • Treatment Outcome

Associated data

  • ClinicalTrials.gov/NCT00977236