Myopia
Conditions
Keywords
children, corneal reshaping, myopia, myopia progression, orthokeratology
Brief summary
The primary aim of this study is to compare eyeball elongation in existing ortho-k subjects who stop the treatment with subjects who continue ortho-k lens wear and control subjects wearing single-vision glasses.
Detailed description
Children wearing ortho-k have been shown to have slower rate of myopic progression than those wearing single-vision spectacles (Cho et al. 2005) or soft lenses (Walline et al. 2009). Both studies showed that the effect of myopic control was most significant during the first six months of the treatment. It is unknown whether the myopic control effect would dissipate upon the discontinuation of the treatment or whether the myopic control effect only happened in the first six month of lens wear and was maintained thereafter. The current study aims at evaluating the effect of discontinuation of ortho-k treatment on myopic control in children who are currently on the treatment. This knowledge is necessary and important as patients/parents have concerns about the permanent dependency on ortho-k once they enrolled in the treatment. Children who have been on the treatment for two years and have recently completed the myopic control studies at The Hong Kong Polytechnic University, i.e. the ROMIO, TO-SEE and HM-PRO studies, will be invited to participate in this 14-month study. Ortho-k subjects will be randomly assigned to study group or the ortho-k control group. The study group subjects will be required to stop lens wear for 7 months at the completion of the previous study (Phase I) and resume lens wear for next 7 months (Phase II). The ortho-k control group subjects will be required to continue the current treatment for another 14 months. Control subjects in the existing myopic control studies will be required to continue using the same treatment, i.e. single-vision glasses, for another 14 months. Rate of myopic progression among the 3 groups and at the two study phases will be determined and compared.
Interventions
DEVICEortho-k lenses
nightly wear of orthokeratology lenses to correct vision
DEVICEsingle-vision glasses
daily wear of spectacle glasses to correct vision
Sponsors
Menicon Co., Ltd.
The Hong Kong Polytechnic University
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
SINGLE (Outcomes Assessor)
Eligibility
Sex/Gender
ALL
Age
8 Years to 14 Years
Healthy volunteers
Yes
Inclusion criteria
* Age 8-14 years old (inclusive) * Subjects who have completed the ROMIO, TO-SEE or HM-PRO studies at The Hong Kong Polytechnic University * Willingness to be randomized into groups (for ortho-k subjects) * Availability for follow-up for at least 14 months
Exclusion criteria
* Non-compliance to the follow up schedule * Non-compliance to the assigned optical correction (i.e. single-vision glasses or ortho-k lenses) * Contraindication for contact lens wear and ortho-k (e.g. limbus to limbus corneal cylinder and dislocated corneal apex) * 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)
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change in Axial Length | Baseline, 7 months, and 14 months after baseline | To determine the changes in axial length in the first 7 months and the last 7 months in the three groups of subjects |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Incidence of Adverse Effects | 14 months | The observation of serious and non-serious adverse events in the 14 months of study period |
Countries
China
Participant flow
Participants by arm
| Arm | Count |
|---|---|
| Single-vision Glasses and Ortho-k Lenses Children who are currently wearing ortho-k lenses at night for correction of refractive errors will be switched to wear single-vision glasses for the first 7 months and then switched back to ortho-k lenses for the next 7 months
ortho-k lenses: nightly wear of orthokeratology lenses to correct vision
single-vision glasses: daily wear of spectacle glasses to correct vision | 18 |
| Ortho-k Lenses Children who are currently wearing ortho-k lenses at night for the correction of refractive errors will continue with the current treatment and serve as the first control group
ortho-k lenses: nightly wear of orthokeratology lenses to correct vision | 19 |
| Single-vision Glasses Children who are currently wearing single-vision spectacles in the daytime for correcting their refractive errors will continue with the current treatment and serve as the second control group
single-vision glasses: daily wear of spectacle glasses to correct vision | 16 |
| Total | 53 |
Baseline characteristics
| Characteristic | Single-vision Glasses and Ortho-k Lenses | Ortho-k Lenses | Single-vision Glasses | Total |
|---|---|---|---|---|
| Age, Continuous | 10 years | 11 years | 11 years | 11 years |
| Axial length | 24.83 mm STANDARD_DEVIATION 0.881 | 24.62 mm STANDARD_DEVIATION 0.772 | 24.72 mm STANDARD_DEVIATION 0.85 | 24.72 mm STANDARD_DEVIATION 0.823 |
| Race/Ethnicity, Customized Chinese | 18 Participants | 19 Participants | 16 Participants | 53 Participants |
| Region of Enrollment China | 18 Participants | 19 Participants | 16 Participants | 53 Participants |
| Sex: Female, Male Female | 7 Participants | 11 Participants | 8 Participants | 26 Participants |
| Sex: Female, Male Male | 11 Participants | 8 Participants | 8 Participants | 27 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk | EG002 affected / at risk |
|---|---|---|---|
| deaths Total, all-cause mortality | — / — | — / — | — / — |
| other Total, other adverse events | 1 / 18 | 0 / 19 | 0 / 16 |
| serious Total, serious adverse events | 0 / 18 | 0 / 19 | 0 / 16 |
Outcome results
Primary
Change in Axial Length
To determine the changes in axial length in the first 7 months and the last 7 months in the three groups of subjects
Time frame: Baseline, 7 months, and 14 months after baseline
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Single-vision Glasses and Ortho-k Lenses | Change in Axial Length | Phase I (first 7 months) | 0.153 mm | Standard Deviation 0.021 |
| Single-vision Glasses and Ortho-k Lenses | Change in Axial Length | Phase II (last 7 months) | 0.059 mm | Standard Deviation 0.014 |
| Ortho-k Lenses | Change in Axial Length | Phase I (first 7 months) | 0.087 mm | Standard Deviation 0.02 |
| Ortho-k Lenses | Change in Axial Length | Phase II (last 7 months) | 0.068 mm | Standard Deviation 0.013 |
| Single-vision Glasses | Change in Axial Length | Phase I (first 7 months) | 0.082 mm | Standard Deviation 0.022 |
| Single-vision Glasses | Change in Axial Length | Phase II (last 7 months) | 0.064 mm | Standard Deviation 0.015 |
Secondary
Incidence of Adverse Effects
The observation of serious and non-serious adverse events in the 14 months of study period
Time frame: 14 months
| Arm | Measure | Group | Value (COUNT_OF_PARTICIPANTS) |
|---|---|---|---|
| Single-vision Glasses and Ortho-k Lenses | Incidence of Adverse Effects | Serious adverse events | 0 Participants |
| Single-vision Glasses and Ortho-k Lenses | Incidence of Adverse Effects | non-serious adverse events | 1 Participants |
| Ortho-k Lenses | Incidence of Adverse Effects | Serious adverse events | 0 Participants |
| Ortho-k Lenses | Incidence of Adverse Effects | non-serious adverse events | 0 Participants |
| Single-vision Glasses | Incidence of Adverse Effects | Serious adverse events | 0 Participants |
| Single-vision Glasses | Incidence of Adverse Effects | non-serious adverse events | 0 Participants |