Myopic ProgressionNCT02643875
Investigation of the Effect of Short-term Orthokeratology With Increased Compression Factor on Ocular Parameters
A study testing Orthokeratology in people with Myopic Progression, run by The Hong Kong Polytechnic University at 1 site in China.
Trial summary
Orthokeratology (ortho-k) is a clinical technique that uses reverse geometry rigid gas permeable contact lens exerting positive pressure on the central cornea to temporary reduce refractive error. Read more about this study
- Who is it for?
- Ages 6 to 10 yearsHealthy volunteers can take part
- Conditions the study is for
- Myopic Progression
- What is being tested?
- Orthokeratology
- Type of treatment
- Medical device
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 36 participants
- Where
- 1 siteChina
- Study dates
- 26 Feb 2016to 18 Nov 2016
- Phase
- Interventional
- Are there results?
- Yes, posted in the registrySummary in the doctors' view
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 6 to 10 years
- All sexes
- Healthy volunteers accepted
- Child
Who may be able to join
- 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
Who cannot join
- 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
Trial locations and contacts
1 site in 1 country.
About this study
Orthokeratology (ortho-k) is a clinical technique that uses reverse geometry rigid gas permeable contact lens exerting positive pressure on the central cornea to temporary reduce refractive error. Researchers have shown that this treatment is effective for myopia control in low to high myopes, with and without astigmatism. Most designs of ortho-k lenses in the market are fitted based on the Jessen formula. The compression factor was introduced to compensate for the regression of the ortho-k effect during the no lens-wear period, so that the wearer can obtain clear distance vision throughout the day and most lens designs use a compression factor of 0.50-0.75 D. However, in a retrospective study (mixed brands of ortho-k lenses), it showed that most patients did not achieve an over-correction of 0.75 D. In order to achieve an over-correction of 0.75 D, an extra flattening power of about 1.50 D instead of 0.75 D should be be targeted. The increased compression factor is expected to increase the target reduction and it may play a role in myopic control and providing a higher successful rate in fitting ortho-k lenses.
Read the detailed description
Subjects were fitted with ortho-k lenses of conventional (0.75 D) and increased (1.75 D) compression factor. The laterality of the compression factor for each subject was randomised.
Subjects were instructed and trained with proper lens handling and disinfection procedures. Lenses were given to the subjects only when they demonstrated proper techniques.
All subjects were required to attend regular follow-ups (baseline, first overnight, and weekly over one-month period). The follow-ups were scheduled (except for the first overnight which was scheduled in the early morning) at a similar time to the baseline visit (+/- 2 hours) to minimise any potential influence of diurnal variation on ocular biometrics.
Additional unscheduled visits were provided when necessary to ensure good ocular health and vision throughout the study period.
- Conditions
- Myopic Progression
- Being tested
- Orthokeratology
- Keywords
- myopia control, orthokeratology
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
OrthokeratologyDevice
It is a kind of rigid permeable lens.
| Study group | Role | What they receive |
|---|---|---|
| Ortho-k lens with normal compression factor | Sham comparator | The eye wears ortho-k lens with normal compression factor to achieve plano (+/- 0.25D) correction. Receives: Device: Orthokeratology |
| Ortho-k lenses with increased compression factor | Active comparator | The eye wears ortho-k lenses with increased compression factor to achieve 1 diopter (+/- 0.25D) over correction. Receives: Device: Orthokeratology |
What is being measured
The primary outcome is the main question the study is designed to answer.
Changes in Spherical Equivalent Refraction
Maximum plus for maximum visual acuity was used as the criterion for subjective refraction.
Spherical equivalent refraction was calculated by adding the sum of the sphere power with half of the cylinder power.
Measured: baseline and one month
Secondary outcomes (2)
Changes in Subfoveal Choroidal Thickness
The subfoveal choroidal thickness was determined as the thickness between the outer retinal pigment epithelium/Bruch's membrane complex and the inner chorioscleral interface.
Measured: baseline and one month
Changes in Higher Order Aberrations
Ocular higher order aberrations were measured using Shack-Hartmann aberrometer. The wavefront data was fitted with a sixth order Zernike polynomial over a 5-mm pupil size.
Measured: baseline and one month
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted31 Dec 2015 (estimated)
- Study start26 Feb 2016
- Primary completion18 Nov 2016
- Study completion18 Nov 2016
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Publications (7)Papers the sponsor has linked to this study.
- Other trials for Myopic ProgressionStudies of the same condition, open and under way.
- More trials run by The Hong Kong Polytechnic UniversityThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Single group
- Masking
- Double blind
- Who is masked
- Participant, Outcomes assessor
- Enrolment
- 36 participants (actual)
Sponsor and investigators
- Lead sponsor
- The Hong Kong Polytechnic University
- Sponsor type
- University, hospital or other
- Collaborators
- Menicon Co., Ltd., Queensland University of Technology, Aston University
- Responsible party
- Principal investigator, Pauline Cho, The Hong Kong Polytechnic University
- Investigators
- Pauline Cho, PhD, Principal investigator, The Hong Kong Polytechnic University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT02643875
- Sponsor's protocol ID
- HSEARS20151002004
- Status last verified
- Feb 2020
- First submitted
- 28 Dec 2015
- Last updated
- 18 Sep 2020
- Results posted
- Yes, on ClinicalTrials.gov
Publications
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. doi: 10.1080/02713680590907256.
PubMed 15875367Cho 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.
PubMed 22969068Chen 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.
PubMed 24003088Chan 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.
PubMed 18426426Wan K, Lau JK, Cheung SW, Cho P. Refractive and corneal responses of young myopic children to short-term orthokeratology treatment with different compression factors. Cont Lens Anterior Eye. 2020 Feb;43(1):65-72. doi: 10.1016/j.clae.2019.10.134. Epub 2019 Nov 6.
PubMed 31704093Lau JK, Vincent SJ, Cheung SW, Cho P. The influence of orthokeratology compression factor on ocular higher-order aberrations. Clin Exp Optom. 2020 Jan;103(1):123-128. doi: 10.1111/cxo.12933. Epub 2019 Jul 1.
PubMed 31264269Lau JK, Wan K, Cheung SW, Vincent SJ, Cho P. Weekly Changes in Axial Length and Choroidal Thickness in Children During and Following Orthokeratology Treatment With Different Compression Factors. Transl Vis Sci Technol. 2019 Jul 23;8(4):9. doi: 10.1167/tvst.8.4.9. eCollection 2019 Jul.
PubMed 31360614
Study at a glance
From the registry record, last updated by the sponsor on 18 Sep 2020. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Investigation of the Effect of Short-term Orthokeratology With Increased Compression Factor on Ocular Parameters
- ClinicalTrials.gov ID
- NCT02643875
- Acronym / sponsor ID
- HSEARS20151002004
- Conditions
- Myopic Progression
- Keywords
- myopia control, orthokeratology
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 36 participants (actual)
- Lead sponsor
- The Hong Kong Polytechnic UniversityUniversity, hospital or other
- Collaborators
- Menicon Co., Ltd., Queensland University of Technology, Aston University
- Study start
- 26 Feb 2016 (actual)
- Primary completion
- 18 Nov 2016 (actual)
- Study completion
- 18 Nov 2016 (actual)
- First posted
- 31 Dec 2015 (estimated)
- Results
- Posted 18 Sep 2020
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Orthokeratology (ortho-k) is a clinical technique that uses reverse geometry rigid gas permeable contact lens exerting positive pressure on the central cornea to temporary reduce refractive error. Researchers have shown that this treatment is effective for myopia control in low to high myopes, with and without astigmatism. Most designs of ortho-k lenses in the market are fitted based on the Jessen formula. The compression factor was introduced to compensate for the regression of the ortho-k effect during the no lens-wear period, so that the wearer can obtain clear distance vision throughout the day and most lens designs use a compression factor of 0.50-0.75 D. However, in a retrospective study (mixed brands of ortho-k lenses), it showed that most patients did not achieve an over-correction of 0.75 D. In order to achieve an over-correction of 0.75 D, an extra flattening power of about 1.50 D instead of 0.75 D should be be targeted. The increased compression factor is expected to increase the target reduction and it may play a role in myopic control and providing a higher successful rate in fitting ortho-k lenses.
Detailed description
Subjects were fitted with ortho-k lenses of conventional (0.75 D) and increased (1.75 D) compression factor. The laterality of the compression factor for each subject was randomised.
Subjects were instructed and trained with proper lens handling and disinfection procedures. Lenses were given to the subjects only when they demonstrated proper techniques.
All subjects were required to attend regular follow-ups (baseline, first overnight, and weekly over one-month period). The follow-ups were scheduled (except for the first overnight which was scheduled in the early morning) at a similar time to the baseline visit (+/- 2 hours) to minimise any potential influence of diurnal variation on ocular biometrics.
Additional unscheduled visits were provided when necessary to ensure good ocular health and vision throughout the study period.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Single group
- Masking
- Double blind (participant, outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Ortho-k lens with normal compression factor | Sham comparator | Device: OrthokeratologyThe eye wears ortho-k lens with normal compression factor to achieve plano (+/- 0.25D) correction. |
| Ortho-k lenses with increased compression factor | Active comparator | Device: OrthokeratologyThe eye wears ortho-k lenses with increased compression factor to achieve 1 diopter (+/- 0.25D) over correction. |
Who may qualify
- Ages
- 6 to 10 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Child
Key inclusion criteria (6 listed)
- 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
Key exclusion criteria (7 listed)
- 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)
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| OrthokeratologyIt is a kind of rigid permeable lens. | Device | Ortho-k lens with normal compression factor, Ortho-k lenses with increased compression factor |
Primary outcome
Changes in Spherical Equivalent Refraction
Time frame: baseline and one month
Maximum plus for maximum visual acuity was used as the criterion for subjective refraction. Spherical equivalent refraction was calculated by adding the sum of the sphere power with half of the cylinder power.
2 secondary outcomes
Changes in Subfoveal Choroidal Thickness
Time frame: baseline and one month
Changes in Higher Order Aberrations
Time frame: baseline and one month
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 18 Sep 2020.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
- Background: PubMed 15875367Cho 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. doi: 10.1080/02713680590907256.
- Background: PubMed 22969068Cho 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.
- Background: PubMed 24003088Chen 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.
- Background: PubMed 18426426Chan 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.
- Results publication: PubMed 31704093Wan K, Lau JK, Cheung SW, Cho P. Refractive and corneal responses of young myopic children to short-term orthokeratology treatment with different compression factors. Cont Lens Anterior Eye. 2020 Feb;43(1):65-72. doi: 10.1016/j.clae.2019.10.134. Epub 2019 Nov 6.
- Results publication: PubMed 31264269Lau JK, Vincent SJ, Cheung SW, Cho P. The influence of orthokeratology compression factor on ocular higher-order aberrations. Clin Exp Optom. 2020 Jan;103(1):123-128. doi: 10.1111/cxo.12933. Epub 2019 Jul 1.
- Results publication: PubMed 31360614Lau JK, Wan K, Cheung SW, Vincent SJ, Cho P. Weekly Changes in Axial Length and Choroidal Thickness in Children During and Following Orthokeratology Treatment With Different Compression Factors. Transl Vis Sci Technol. 2019 Jul 23;8(4):9. doi: 10.1167/tvst.8.4.9. eCollection 2019 Jul.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Pauline Cho, PhD principal investigator
The Hong Kong Polytechnic University
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Orthokeratology in people with Myopic Progression, run by The Hong Kong Polytechnic University at 1 site in China.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 6 inclusion and 7 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 18 Sep 2020. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in China. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
Yes. Results are posted in the registry (first posted 18 Sep 2020). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Changes in Spherical Equivalent Refraction (time frame: baseline and one month). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT02643875, which also lists 7 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 18 Sep 2020.