Clinical trial NCT00977236: Myopic Control for High Myopes Using Orthokeratology
Official title: High Myopia - Partial Reduction Orthokeratology Study
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Myopia
Keywords: children
corneal reshaping
myopia
myopia control
orthokeratology
Lead sponsor: The Hong Kong Polytechnic University
Sponsor class: OTHER
Collaborators: name: Procornea Nederland B.V.
First posted: 2009-09-15
Enrollment: 52
Sex: ALL
Minimum age (years): 8
Maximum age (years): 11
Standard ages: CHILD
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: TREATMENT

Brief summary: 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.

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.

Eligibility criteria: 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)

Primary outcomes:
measure: Determine the change in cycloplegic axial length in the study and control groups
timeFrame: 2 years
Secondary outcomes:
measure: Determine the incidence of adverse effects in cornea, the palpebral, bulbar and tarsal conjunctiva in the study and the control groups
timeFrame: 2 years
measure: Rate of regression during the daytime
timeFrame: 2 years
Other outcomes:
Locations:
city: Hong Kong SAR
country: China
facility: School of Optometry, The Hong Kong Polytechnic University
Study officials:
affiliation: The Hong Kong Polytechnic University
name: Pauline Cho
role: PRINCIPAL_INVESTIGATOR
References:
citation: Cho P, Cheung SW, Edwards M. The longitudinal orthokeratology research in children (LORIC) in Hong Kong: a pilot study on refractive changes and myopic control. Curr Eye Res. 2005 Jan;30(1):71-80. doi: 10.1080/02713680590907256.
citation: Walline JJ, Jones LA, Sinnott LT. Corneal reshaping and myopia progression. Br J Ophthalmol. 2009 Sep;93(9):1181-5. doi: 10.1136/bjo.2008.151365. Epub 2009 May 4.
citation: Charm J, Cho P. 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.
citation: Charm J, Cho P. High myopia-partial reduction orthokeratology (HM-PRO): study design. Cont Lens Anterior Eye. 2013 Aug;36(4):164-70. doi: 10.1016/j.clae.2013.02.012. Epub 2013 Mar 18.