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Trial registered on ANZCTR
Registration number
ACTRN12618000187246
Ethics application status
Approved
Date submitted
31/01/2018
Date registered
5/02/2018
Date last updated
22/02/2019
Date data sharing statement initially provided
22/02/2019
Type of registration
Prospectively registered
Titles & IDs
Public title
Comparing short sighted refraction profiles created by two different designs of an orthokeratology contact lens
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Scientific title
Changes in peripheral optics with two different orthokeratology lens designs for patients with myopia
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Secondary ID [1]
293927
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None
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Universal Trial Number (UTN)
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Trial acronym
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Linked study record
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Health condition
Health condition(s) or problem(s) studied:
Myopia
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Condition category
Condition code
Eye
305503
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0
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Diseases / disorders of the eye
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Intervention/exposure
Study type
Interventional
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Description of intervention(s) / exposure
Two different orthokeratology lens designs are to be worn in randomised order for a period of 1 week overnight wear each, after which purposely induced changes to corneal shape and associated effect on refraction profile will be measured and compared, with a minimum 1 week duration washout period between the two iterations where no lenses will be worn. Each iteration will be worn overnight only in both eyes for a minimum of 5 hours and maximum of 12 hours.The orthokeratology lenses will be fitted by university researchers under the direct supervision of qualified University of New South Wales (UNSW), Sydney, employed optometrists. Participants will be required to self insert the lenses at their home before sleep and remove them on waking, with all training and support on how to insert and remove lenses and deal with any lens adherence provided. After each week of overnight wear participants will be required to return to UNSW for study measurements. Participants will be required to attend the study centre after the first night of lens wear to assess lens fit and to ensure that participants are successful in removing the lenses and in taking the correct cleaning and storage steps unguided. Participants will not be allowed to continue with the study until they are competent at removing and caring for the lenses without guidance. In the unlikely case that a participant has found the lens to be bound and can't be loosened with the resolution steps provided they will be instructed to contact the investigators for advice.
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Intervention code [1]
300194
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Treatment: Devices
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Comparator / control treatment
Double blind repeated measures design with each of the two orthokeratology lens designs issued for wear in a randomised order. No need for a control group.
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Control group
Active
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Outcomes
Primary outcome [1]
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Changes to anterior eye shape profile will be measured using a Medmont E300 corneal topographer.
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Assessment method [1]
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Timepoint [1]
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In the morning before starting wear and in the morning after 7 nights of wear for each of the two orthokeratology lens designs being investigated.
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Secondary outcome [1]
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Changes to peripheral refraction will be measured across the horizontal meridian using the Shin_Nippon NVisionK 5001 autorefractor
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Assessment method [1]
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Timepoint [1]
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In the morning before starting wear and in the morning after 7 nights of wear for each of the two orthokeratology lens designs being investigated.
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Eligibility
Key inclusion criteria
1. Healthy individuals aged between 18-40
2. Have short-sightedness (myopia) between -1.ooD and -4.ooD and less than -1.50D of corneal astigmatism
3. No previous rigid contact lens wear
4. Have good ocular health and general health
5. No contraindications to rigid contact lens wear
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Minimum age
18
Years
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Maximum age
40
Years
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Sex
Both males and females
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Can healthy volunteers participate?
No
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Key exclusion criteria
1. Strabismus or amblyopia
2. Systemic or ocular conditions that may affect tear quality or contact lens wear or that may affect refractive development
3. Previous history or ocular surgery, trauma, or chronic ocular disease
4. Ocular or systemic medication use that may interfere with contact lens wear or ocular surface
5. Not willing to comply with the allocated treatment and follow-up scheduole
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Study design
Purpose of the study
Treatment
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Allocation to intervention
Randomised controlled trial
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Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
The order of wear for the two orthokeratology lens designs will be controlled by off-site by the contact lens lab providing the lenses. The lab will issue both sets of orthokeratology lenses in identical packets other than one being marked 'first to be worn' and the other 'second to be worn'. Order of allocation will be recorded by the lab and issued to the researcher conducting data analysis once all participants have completed the study. For an additional layer of clarification each orthokeratology lens will be engraved by the lab with a unique number that will be recorded by the researcher recording the study measurements so that at data analysis stage the lenses actually worn according to researcher observation can be cross referenced to the lens supply schedule recorded by the lab.
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Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Simple randomisation using a randomisation table created by computer software.
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Masking / blinding
Blinded (masking used)
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Who is / are masked / blinded?
The people receiving the treatment/s
The people administering the treatment/s
The people assessing the outcomes
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Intervention assignment
Crossover
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Other design features
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Phase
Not Applicable
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Type of endpoint/s
Efficacy
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Statistical methods / analysis
Prior data indicate that to conduct a study that is able to detect a difference of 0.1 D in mid-peripheral corneal refractive power, with a study power of 0.80 at the 5% level of statistical significance and taking into consideration a 20% drop out rate, 15 subjects will be required for this study. The Type I error probability associated with this test of this null hypothesis is 0.05. Repeated measures t-tests will be used to compare change to corneal shape profile and peripheral refraction profile over the 1 week wearing period of overnight wear between the two orthokeratology lens designs.
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Recruitment
Recruitment status
Completed
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Date of first participant enrolment
Anticipated
26/02/2018
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Actual
8/05/2018
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Date of last participant enrolment
Anticipated
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Actual
30/11/2018
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Date of last data collection
Anticipated
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Actual
17/12/2018
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Sample size
Target
15
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Accrual to date
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Final
17
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Recruitment in Australia
Recruitment state(s)
NSW
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Funding & Sponsors
Funding source category [1]
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University
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Name [1]
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University of New South Wales
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Address [1]
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School of Optometry and Vision Science, University of New South Wales, Gate 14, Barker St, Rupert Myers Building (North Wing), Kensington, NSW, 2033
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Country [1]
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Australia
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Primary sponsor type
University
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Name
University of New South Wales
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Address
School of Optometry and Vision Science, University of New South Wales, Gate 14, Barker St, Rupert Myers Building (North Wing), Kensington, NSW, 2033
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Country
Australia
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Secondary sponsor category [1]
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None
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Name [1]
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Address [1]
297702
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Country [1]
297702
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Ethics approval
Ethics application status
Approved
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Ethics committee name [1]
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UNSW Human Research Ethics Committee
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Ethics committee address [1]
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UNSW Research Ethics & Compliance Support University of New South Wales Gate 14, Barker St Rupert Myers Building (South Wing) Kensington, NSW, 2033
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Ethics committee country [1]
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Australia
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Date submitted for ethics approval [1]
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05/02/2018
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Approval date [1]
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08/03/2018
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Ethics approval number [1]
299523
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HC17954
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Summary
Brief summary
Myopia (short sightedness) is a refractive condition where the distance from the front to the back of the eye is too long for the refractive strength of the eye, leading to light being focussed in front of the retina (light sensitive layer on the inside back of the eye) and subsequently causing blurred vision. Myopia typically develops in childhood while the eye is growing and is believed to be accelerated by correcting the myopia with glasses. When myopia first presents the child complains of poor distance vision which is corrected by glasses. Unfortunately, myopia continues to progress requiring the child to return at regular intervals to get ever stronger glasses, until they reach adulthood. Orthokeratology (OK) lenses are specialised contact lenses that are worn during sleep to reshape the front surface of the eye to temporarily correct myopia. Recent research has shown that OK lenses are effective at slowing progression of myopia by 50%. These encouraging results have led contact lens manufacturers to develop OK lens designs with greater effectivity in slowing progression of myopia. While these ‘Myopia Control’ OK lenses are now being supplied to optometry practices and marketed as being more effective in slowing progression of myopia compared to standard OK lens designs, there is no scientific evidence to support that they are any more effective than standard OK designs. The aim of this project is to increase understanding on how myopia control OK lens designs will affect known stimuluses for myopia progression compared to standard OK lens designs. The scientific literature reveals that OK causes peripheral light rays to be focussed further towards the front of the eye than central light rays, which is termed peripheral myopic defocus. Peripheral myopic defocus has been shown to slow progression of myopia in animal models, and this same mechanism is believed to be the reason why OK lenses slow progression of myopia. The manufacturers of myopia control OK lens designs claim that they are more effective at slowing progression of myopia compared to standard OK lens designs because they create a greater amount of peripheral myopic defocus. We are going to investigate the potential for greater slowing of myopia progression with myopia control OK lens designs, by measuring the effect that the different OK designs have on myopic defocus in young adults over 1 week of wear, which is the reported shortest duration of time for the full refractive effect to be achieved. This study is important as optometrists need to know the true effect that OK lenses marketed to slow myopia progression have on refractive mechanisms that have been shown to retard progression of myopia, if they are to be effective in managing myopia in their child patients. Outcomes will also assist the design of future longitudinal studies using standard and myopia control OK lens designs.
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Trial website
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Trial related presentations / publications
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Public notes
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Contacts
Principal investigator
Name
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Dr Paul Gifford
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Address
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School of Optometry and Vision Science University of New South Wales
Gate 14, Barker St
Rupert Myers Building (North Wing) Kensington, NSW, 2033
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Country
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Australia
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Phone
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+61423489596
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Fax
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Email
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[email protected]
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Contact person for public queries
Name
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Paul Kang
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Address
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School of Optometry and Vision Science University of New South Wales
Gate 14, Barker St
Rupert Myers Building (North Wing) Kensington, NSW, 2033
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Country
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Australia
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Phone
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+61 2 9385 9816
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Fax
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Email
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[email protected]
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Contact person for scientific queries
Name
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Paul Gifford
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Address
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School of Optometry and Vision Science University of New South Wales
Gate 14, Barker St
Rupert Myers Building (North Wing) Kensington, NSW, 2033
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Country
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Australia
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Phone
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+61423489596
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Fax
80716
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Email
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[email protected]
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Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No
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No/undecided IPD sharing reason/comment
Subject data is de-personalised.
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What supporting documents are/will be available?
No Supporting Document Provided
Results publications and other study-related documents
Documents added manually
No documents have been uploaded by study researchers.
Documents added automatically
No additional documents have been identified.
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