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Toric Orthokeratology - Slowing Eye Elongation (TO-SEE)

Primary Purpose

Myopia, Astigmatism

Status
Completed
Phase
Not Applicable
Locations
China
Study Type
Interventional
Intervention
Toric Orthokeratology lenses
Single-vision spectacles
Sponsored by
The Hong Kong Polytechnic University
About
Eligibility
Locations
Arms
Outcomes
Full info

About this trial

This is an interventional treatment trial for Myopia focused on measuring Myopia, Astigmatism, Orthokeratology, Corneal thickness, Corneal curvatures, Corneal biomechanics

Eligibility Criteria

6 Years - 12 Years (Child)All SexesAccepts Healthy Volunteers

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)

Sites / Locations

  • School of Optometry, The Hong KOng Polytechnic University

Arms of the Study

Arm 1

Arm 2

Arm Type

Experimental

Other

Arm Label

Toric orthokeratology lenses

Single-vision spectacles

Arm Description

Children wearing toric ortho-k lenses at night for correcting astigmatism and myopia will be the study group

Children wearing single-vision spectacles in the daytime for correcting the refractive error will be serve as control group

Outcomes

Primary Outcome Measures

To determine the eyeball elongation in children wearing ortho-k lenses

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
To investigative the efficacy of toric orthokeratology for correcting astigmatism and myopia

Full Information

First Posted
September 16, 2009
Last Updated
February 18, 2016
Sponsor
The Hong Kong Polytechnic University
Collaborators
Menicon Co., Ltd.
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1. Study Identification

Unique Protocol Identification Number
NCT00978692
Brief Title
Toric Orthokeratology - Slowing Eye Elongation
Acronym
TO-SEE
Official Title
Toric Orthokeratology for Slowing Eye Elongation in Astigmatic Children
Study Type
Interventional

2. Study Status

Record Verification Date
February 2016
Overall Recruitment Status
Completed
Study Start Date
May 2008 (undefined)
Primary Completion Date
July 2012 (Actual)
Study Completion Date
December 2012 (Actual)

3. Sponsor/Collaborators

Responsible Party, by Official Title
Principal Investigator
Name of the Sponsor
The Hong Kong Polytechnic University
Collaborators
Menicon Co., Ltd.

4. Oversight

Data Monitoring Committee
No

5. Study Description

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.
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.

6. Conditions and Keywords

Primary Disease or Condition Being Studied in the Trial, or the Focus of the Study
Myopia, Astigmatism
Keywords
Myopia, Astigmatism, Orthokeratology, Corneal thickness, Corneal curvatures, Corneal biomechanics

7. Study Design

Primary Purpose
Treatment
Study Phase
Not Applicable
Interventional Study Model
Parallel Assignment
Masking
Investigator
Allocation
Non-Randomized
Enrollment
80 (Actual)

8. Arms, Groups, and Interventions

Arm Title
Toric orthokeratology lenses
Arm Type
Experimental
Arm Description
Children wearing toric ortho-k lenses at night for correcting astigmatism and myopia will be the study group
Arm Title
Single-vision spectacles
Arm Type
Other
Arm Description
Children wearing single-vision spectacles in the daytime for correcting the refractive error will be serve as control group
Intervention Type
Device
Intervention Name(s)
Toric Orthokeratology lenses
Other Intervention Name(s)
corneal reshaping therapy
Intervention Description
Children wearing toric orthokeratology at night for correcting astigmatism and myopia will be the study group
Intervention Type
Device
Intervention Name(s)
Single-vision spectacles
Other Intervention Name(s)
glasses
Intervention Description
Children wearing single-vision spectacles in the daytime for correcting the refractive errors will serve as the control group
Primary Outcome Measure Information:
Title
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 Measure Information:
Title
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
Title
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

10. Eligibility

Sex
All
Minimum Age & Unit of Time
6 Years
Maximum Age & Unit of Time
12 Years
Accepts Healthy Volunteers
Accepts Healthy Volunteers
Eligibility 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)
Overall Study Officials:
First Name & Middle Initial & Last Name & Degree
Pauline Cho, PhD
Organizational Affiliation
The Hong Kong Polytechnic University
Official's Role
Principal Investigator
Facility Information:
Facility Name
School of Optometry, The Hong KOng Polytechnic University
City
Hong Kong SAR
Country
China

12. IPD Sharing Statement

Citations:
PubMed Identifier
24003088
Citation
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.
Results Reference
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PubMed Identifier
22561203
Citation
Chen CC, Cheung SW, Cho P. Toric orthokeratology for highly astigmatic children. Optom Vis Sci. 2012 Jun;89(6):849-55. doi: 10.1097/OPX.0b013e318257c20f.
Results Reference
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PubMed Identifier
21895768
Citation
Chen C, Cho P. Toric orthokeratology for high myopic and astigmatic subjects for myopic control. Clin Exp Optom. 2012 Jan;95(1):103-8. doi: 10.1111/j.1444-0938.2011.00616.x. Epub 2011 Sep 5. No abstract available.
Results Reference
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Toric Orthokeratology - Slowing Eye Elongation

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