This site became the new on June 19th. Learn more.
Show more Menu IMPORTANT: Listing of a study on this site does not reflect endorsement by the National Institutes of Health. Talk with a trusted healthcare professional before volunteering for a study. Read more... Menu IMPORTANT: Talk with a trusted healthcare professional before volunteering for a study. Read more... Menu
Give us feedback

Myopic Control for High Myopes Using Orthokeratology (HM-PRO)

This study has been completed.
Procornea Nederland B.V.
Information provided by (Responsible Party):
Pauline Cho, The Hong Kong Polytechnic University Identifier:
First received: September 14, 2009
Last updated: July 11, 2013
Last verified: July 2013
The purpose of this study is to evaluate and compare the eyeball elongation in high myopic children using partial correction orthokeratology and single-vision spectacles.

Condition Intervention
Myopia Device: Orthokeratology lenses Device: Single-vision spectacle lenses

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single (Investigator)
Primary Purpose: Treatment
Official Title: High Myopia - Partial Reduction Orthokeratology Study

Resource links provided by NLM:

Further study details as provided by Pauline Cho, The Hong Kong Polytechnic University:

Primary Outcome Measures:
  • Determine the change in cycloplegic axial length in the study and control groups [ Time Frame: 2 years ]

Secondary Outcome Measures:
  • Determine the incidence of adverse effects in cornea, the palpebral, bulbar and tarsal conjunctiva in the study and the control groups [ Time Frame: 2 years ]
  • Rate of regression during the daytime [ Time Frame: 2 years ]

Enrollment: 52
Study Start Date: July 2008
Study Completion Date: December 2012
Primary Completion Date: December 2011 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: Orthokeratology lenses
Children wearing orthokeratology at night for partial correction and spectacles at daytime for residual refractive error will be study group
Device: Orthokeratology lenses
Nightly use of orthokeratology to correct the refractive error and over-specs for a period of two years
Other Name: Corneal reshaping therapy
Single-vision spectacle lenses
Children wearing single-vision spectacles in the daytime for correcting the refractive error will serve as control group
Device: Single-vision spectacle lenses
Daily use of spectacles to correct the refractive error for a period of two years
Other Names:
  • Glasses
  • Spectacles

Detailed Description:

Orthokeratology (ortho-k) has been shown to have strong potential for retardation of myopic progression in low myopes. To date, clinical experience has shown the technique to be less effective in achieving full myopic reduction in high myopes. Would myopic control be possible for high myopes undergoing partial correction ortho-k treatment?

A randomized, longitudinal study is designed to investigate the efficacy of partial correction ortho-k in retardation of myopic progression in high myopic children. Eye growth in terms of axial length elongation in children wearing ortho-k and over-spectacles (to correct residual refractive errors) (study group) and those wearing single-vision spectacles (control group) will be evaluated and compared.


Ages Eligible for Study:   8 Years to 11 Years   (Child)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  • Myopia (refractive sphere): > 5.75D
  • Astigmatism: < ½ of myopia; with-the-rule astigmatism (axes 180 +/- 30) ≤1.25D; astigmatism of other axes ≤ 0.50D
  • Spherical equivalent (SE): > 5.75D
  • Anisometropia: ≤ 1.50D in both refractive sphere, refractive cylinder and SE
  • Best corrected monocular visual acuity: equal to or better than 0.10 in logMAR scale in both eyes
  • Willingness for randomization
  • Availability for follow-up for at least 2 years

Exclusion Criteria:

  • Strabismus at distance or near
  • Contraindication for contact lens wear and orthokeratology (e.g. limbus to limbus corneal cylinder and dislocated corneal apex
  • Systemic or ocular conditions which may affect contact lens wear (e.g. allergy and medication)
  • Systemic or ocular conditions which may affect refractive development (e.g. Down syndrome, ptosis)
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its identifier: NCT00977236

School of Optometry, The Hong Kong Polytechnic University
Hong Kong SAR, China
Sponsors and Collaborators
The Hong Kong Polytechnic University
Procornea Nederland B.V.
Principal Investigator: Pauline Cho The Hong Kong Polytechnic University