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Toric Orthokeratology - Slowing Eye Elongation (TO-SEE)

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details.
 
ClinicalTrials.gov Identifier: NCT00978692
Recruitment Status : Completed
First Posted : September 17, 2009
Last Update Posted : February 22, 2016
Sponsor:
Collaborator:
Menicon Co., Ltd.
Information provided by (Responsible Party):
Pauline Cho, The Hong Kong Polytechnic University

Study Description
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Brief Summary:
The aims of this study are to investigate the effects of ortho-k for astigmatic and myopic reduction and myopic control in children, and the long term effects on corneal curvatures and biomechanics.

Condition or disease Intervention/treatment Phase
Myopia Astigmatism Device: Toric Orthokeratology lenses Device: Single-vision spectacles Not Applicable

Detailed Description:

Ortho-k has been shown to be effective in correcting low myopia but relatively ineffective for astigmatism, using spherical reverse geometry lens designs. Toric ortho-k lenses have been introduced in recent years but the efficacy for astigmatic reduction and for myopic control in children have not been confirmed. The mechanism of myopic reduction in ortho-k cannot be fully explained by changes to the anterior corneal curvatures. It is therefore possible that other corneal parameters such as posterior corneal curvature and corneal biomechanics may contribute to the mechanism.

The current study aims at investigating the efficacy of toric ortho-k lenses for correcting myopic astigmatism and for retarding myopic progression in children compared to children wearing single-vision spectacles. Long term changes to other corneal parameters such as posterior cornea curvatures, topographical corneal thickness, corneal hysteresis, corneal resistance factor, with and without ortho-k lens wear will also be investigated.

Study Design
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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 80 participants
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: Single (Investigator)
Primary Purpose: Treatment
Official Title: Toric Orthokeratology for Slowing Eye Elongation in Astigmatic Children
Study Start Date : May 2008
Actual Primary Completion Date : July 2012
Actual Study Completion Date : December 2012

Resource links provided by the National Library of Medicine


Arms and Interventions
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Arm Intervention/treatment
Experimental: Toric orthokeratology lenses
Children wearing toric ortho-k lenses at night for correcting astigmatism and myopia will be the study group
 Device: Toric Orthokeratology lenses
Children wearing toric orthokeratology at night for correcting astigmatism and myopia will be the study group
Other Name: corneal reshaping therapy
Single-vision spectacles
Children wearing single-vision spectacles in the daytime for correcting the refractive error will be serve as control group
 Device: Single-vision spectacles
Children wearing single-vision spectacles in the daytime for correcting the refractive errors will serve as the control group
Other Name: glasses


Outcome Measures
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Primary Outcome Measures :
  1. To determine the eyeball elongation in children wearing ortho-k lenses [ Time Frame: Before lens wear, 6, 12,18, 24 months after lens wear ]

Secondary Outcome Measures :
  1. To determine the posterior corneal curvatures, topographic corneal thickness, corneal volume, corneal hysteresis and corneal resistance factor in a group of children and compare these parameters with the ortho-k children [ Time Frame: Before lens wear, 6, 12,18, 24 months after lens wear ]
  2. To investigative the efficacy of toric orthokeratology for correcting astigmatism and myopia [ Time Frame: Before lens wear, 6, 12,18, 24 months after lens wear ]

Eligibility Criteria
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Ages Eligible for Study:   6 Years to 12 Years   (Child)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes
Criteria

Inclusion Criteria:

  • Myopia (refractive sphere): more than -0.50DS to -5.00DS
  • Astigmatism: with-the-rule astigmatism more than -1.25DC
  • Anisometropia: ≤ 1.50D in both refractive sphere
  • Best corrected monocular visual acuity: equal to or better than 0.10 in logMAR scale in both eyes
  • 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 myopia 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)
Contacts and Locations
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Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT00978692


Locations
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China
School of Optometry, The Hong KOng Polytechnic University
Hong Kong SAR, China
Sponsors and Collaborators
The Hong Kong Polytechnic University
Menicon Co., Ltd.
Investigators
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Principal Investigator: Pauline Cho, PhD The Hong Kong Polytechnic University
More Information
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Publications:

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Responsible Party: Pauline Cho, Professor, The Hong Kong Polytechnic University
ClinicalTrials.gov Identifier: NCT00978692    
Other Study ID Numbers: H-ZG30
First Posted: September 17, 2009    Key Record Dates
Last Update Posted: February 22, 2016
Last Verified: February 2016
Keywords provided by Pauline Cho, The Hong Kong Polytechnic University:
Myopia
Astigmatism
Orthokeratology
 Corneal thickness
Corneal curvatures
Corneal biomechanics
Additional relevant MeSH terms:
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Myopia
Astigmatism
Refractive Errors
Eye Diseases