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Toric Orthokeratology - Slowing Eye Elongation (TO-SEE)

This study is ongoing, but not recruiting participants.
Sponsor:
Collaborator:
Menicon Co., Ltd.
Information provided by:
The Hong Kong Polytechnic University
ClinicalTrials.gov Identifier:
NCT00978692
First received: September 16, 2009
Last updated: June 22, 2011
Last verified: June 2011
History of Changes
  Purpose

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 Intervention
Myopia
Astigmatism
 Device: Toric Orthokeratology lenses
Device: Single-vision spectacles

Study Type: Interventional
Study Design: Allocation: Non-Randomized
Endpoint Classification: Safety/Efficacy Study
Intervention Model: Parallel Assignment
Masking: Single Blind (Investigator)
Primary Purpose: Treatment
Official Title: Toric Orthokeratology for Slowing Eye Elongation in Astigmatic Children

Resource links provided by NLM:

U.S. FDA Resources

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

Primary Outcome Measures:
  • To determine the eyeball elongation in children wearing ortho-k lenses [ Time Frame: Before lens wear, 6, 12,18, 24 months after lens wear ] [ Designated as safety issue: No ]

Secondary Outcome Measures:
  • 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 ] [ Designated as safety issue: No ]
  • 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 ] [ Designated as safety issue: No ]

Estimated Enrollment: 100
Study Start Date: May 2008
Estimated Study Completion Date: December 2011
Estimated Primary Completion Date: November 2011 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
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

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.

  Eligibility

Ages Eligible for Study:   6 Years to 12 Years
Genders Eligible for Study:   Both
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
Please refer to this study by its ClinicalTrials.gov identifier: NCT00978692

Locations
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
Principal Investigator: Pauline Cho, PhD The Hong Kong Polytechnic University
  More Information

No publications provided

Responsible Party: Dr Pauline Cho, School of Optometry, The Hong Kong Polytechnic University
ClinicalTrials.gov Identifier: NCT00978692     History of Changes
Other Study ID Numbers: H-ZG30
Study First Received: September 16, 2009
Last Updated: June 22, 2011
Health Authority: Hong Kong: Ethics Committee

Keywords provided by The Hong Kong Polytechnic University:
Myopia
Astigmatism
Orthokeratology
 Corneal thickness
Corneal curvatures
Corneal biomechanics

Additional relevant MeSH terms:
Astigmatism
Myopia
Refractive Errors
Eye Diseases

ClinicalTrials.gov processed this record on May 19, 2013