A 2-year Longitudinal Study on the Structural and Optical Effects of Orthokeratology Treatment on Eye

Overview

This is a two-year longitudinal study investigating the optical and structural effects of increased compression factor of orthokeratology lens on eyes and the corresponding effect on change in choroidal thickness and therefore myopic control.

Study Type

  • Study Type: Interventional
  • Study Design
    • Allocation: Randomized
    • Intervention Model: Parallel Assignment
    • Primary Purpose: Treatment
    • Masking: Single (Outcomes Assessor)
  • Study Primary Completion Date: August 3, 2019

Interventions

  • Device: Orthokeratology

Arms, Groups and Cohorts

  • No Intervention: Single-vision glasses
    • Subjects wearing single-vision glasses CR-39 of refractive index 1.56.
  • Sham Comparator: Orthokeratology with normal compression factor
    • Subjects wearing orthokeratology lenses of normal compression factor about 0.50-0.75D.
  • Active Comparator: Orthokeratology with increased compression factor
    • Subjects wearing orthokeratology lenses of increased compression factor about 1.50-1.75D.

Clinical Trial Outcome Measures

Primary Measures

  • Axial length
    • Time Frame: every 6 monthly in 2 years
    • axial progression of the eyeball

Secondary Measures

  • Ocular aberration measured by Complete Ophthalmic Analysis System (COAS) aberrometer
    • Time Frame: every 6 monthly in 2 years
    • ocular aberration measured by Complete Ophthalmic Analysis System (COAS) aberrometer
  • Corneal biomechanics (corneal response using ocular response)
    • Time Frame: every 6 monthly in 2 years
    • corneal response using ocular response
  • Accommodation lag measured by Complete Ophthalmic Analysis System (COAS) aberrometer
    • Time Frame: every 6 monthly in 2 years
    • accommodation lag measured by Complete Ophthalmic Analysis System (COAS) aberrometer using different accommodation targets
  • Choroidal thickness captured by Optical Coherent Tomographer (OCT)
    • Time Frame: every 6 monthly in 2 years
    • choroidal thickness captured by Optical Coherent Tomographer (OCT) and measured using a customized software

Participating in This Clinical Trial

Inclusion Criteria

  • 6 to 10 years old – Myopia: between 0.50 D and 4.00 D in both eyes – Astigmatism: <1.50 D; ≤ 1.25 D for with-the-rule astigmatism (axes 180 ± 30); ≤ 0.50 D for astigmatism of other axes in both eyes – Anisometropia: ≤ 1.50 D – Symmetrical corneal topography with corneal toricity <2.00 D in both eyes – Agree for randomization Exclusion Criteria:

  • Contraindications for orthokeratology wear (e.g. limbus-to-limbus corneal cylinder and dislocated corneal apex) – Any type of strabismus or amblyopia – Myopic treatment (e.g. refractive surgery and progressive lens wear for myopic control) before and during the study period – Rigid contact lenses (including orthokeratology lenses) experience – Systemic condition which might affect refractive development (for example, Down syndrome, Marfan's syndrome) – Ocular conditions which might affect the refractive error (for example, cataract, ptosis) – Poor compliance for lens wear or follow-up

Gender Eligibility: All

Minimum Age: 6 Years

Maximum Age: 10 Years

Are Healthy Volunteers Accepted: Accepts Healthy Volunteers

Investigator Details

  • Lead Sponsor
    • The Hong Kong Polytechnic University
  • Collaborator
    • Menicon Co., Ltd.
  • Provider of Information About this Clinical Study
    • Principal Investigator: Pauline Cho, Professor – The Hong Kong Polytechnic University
  • Overall Official(s)
    • Pauline Cho, PhD, Principal Investigator, The Hong Kong Polytechnic University

References

Lam CS, Lam CH, Cheng SC, Chan LY. Prevalence of myopia among Hong Kong Chinese schoolchildren: changes over two decades. Ophthalmic Physiol Opt. 2012 Jan;32(1):17-24. doi: 10.1111/j.1475-1313.2011.00886.x.

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.

Cho P, Cheung SW. Retardation of myopia in Orthokeratology (ROMIO) study: a 2-year randomized clinical trial. Invest Ophthalmol Vis Sci. 2012 Oct 11;53(11):7077-85. doi: 10.1167/iovs.12-10565.

Chen C, Cheung SW, Cho P. Myopia control using toric orthokeratology (TO-SEE study). Invest Ophthalmol Vis Sci. 2013 Oct 3;54(10):6510-7. doi: 10.1167/iovs.13-12527.

González-Méijome JM, Villa-Collar C, Queirós A, Jorge J, Parafita MA. Pilot study on the influence of corneal biomechanical properties over the short term in response to corneal refractive therapy for myopia. Cornea. 2008 May;27(4):421-6. doi: 10.1097/ICO.0b013e318164e49d.

Wolffsohn JS, Safeen S, Shah S, Laiquzzaman M. Changes of corneal biomechanics with keratoconus. Cornea. 2012 Aug;31(8):849-54. doi: 10.1097/ICO.0b013e318243e42d.

Tse DY, Lam CS, Guggenheim JA, Lam C, Li KK, Liu Q, To CH. Simultaneous defocus integration during refractive development. Invest Ophthalmol Vis Sci. 2007 Dec;48(12):5352-9.

Chan B, Cho P, Mountford J. The validity of the Jessen formula in overnight orthokeratology: a retrospective study. Ophthalmic Physiol Opt. 2008 May;28(3):265-8. doi: 10.1111/j.1475-1313.2008.00545.x.

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