Clinical trial NCT00978679: Peripheral Optics in Myopia and Orthokeratology
Official title: Peripheral Refraction and Aberration in Myopic Progression and Myopic Control
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Myopia
Keywords: Children
Peripheral refraction
Aberration
Eyeball length
Myopic control
Myopia
Corneal reshaping
Orthokeratology
Lead sponsor: The Hong Kong Polytechnic University
Sponsor class: OTHER
Collaborators: name: Menicon Co., Ltd.
First posted: 2009-09-17
Enrollment: 90
Sex: ALL
Minimum age (years): 6
Maximum age (years): 9
Standard ages: CHILD
Accepts healthy volunteers: yes
Allocation: NON_RANDOMIZED
Intervention model: PARALLEL
Primary purpose: TREATMENT

Brief summary: The primary objective of the current study is to investigate changes in peripheral refraction and aberration in children wearing orthokeratology lenses and single-vision spectacles.

Detailed description: Apart from being effective in reducing low to moderate myopia, orthokeratology has been shown to have potential in retarding myopic progression. The central cornea is flattened and peripheral optics altered in orthokeratology and it has been suggested that orthokeratology slows myopic progression through the alteration of peripheral optics. The aim of the current study is to investigate the changes in peripheral refraction and aberration in children wearing orthokeratology (study group) and single-vision spectacles (control group).

Eligibility criteria: Inclusion Criteria:

* Myopia (refractive sphere): \> 0.50D and ≤ 6.00D
* Astigmatism: with-the-rule astigmatism (axes 180 +/- 30) ≤ 1.50D; astigmatism of other axes ≤ 0.50D
* Spherical equivalent (SE): \> 0.50D and ≤ 6.75D (myopia)
* Best corrected monocular visual acuity: equal to or better than 6/7.5 in Snellen scale
* Willingness to wear contact lenses or spectacles on a daily basis
* 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)
* Prior experience with the use of rigid lenses (including orthokeratology)
* Prior experience with myopic control treatment (e.g. refractive therapy or progressive spectacles)
* 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: Changes in cycloplegic off-axial auto-refraction, aberration and eyeball length
timeFrame: 2 years
Secondary outcomes:
Other outcomes:
Locations:
city: Hong Kong
country: China
facility: School of Optometry, The Hong Kong Polytechnic University
state: Hong Kong
Study officials:
affiliation: School of Optometry, The Hong Kong Polytechnic University
name: Pauline Cho, PhD
role: PRINCIPAL_INVESTIGATOR
References:
citation: Mathur A, Atchison DA. Effect of orthokeratology on peripheral aberrations of the eye. Optom Vis Sci. 2009 May;86(5):E476-84. doi: 10.1097/OPX.0b013e31819fa5aa.
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: Charman WN, Mountford J, Atchison DA, Markwell EL. Peripheral refraction in orthokeratology patients. Optom Vis Sci. 2006 Sep;83(9):641-8. doi: 10.1097/01.opx.0000232840.66716.af.