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Orthokeratology (ortho-k) lens is very effective in slowing down axial elongation in myopic children by 30% to 63% when compared to children wearing single-vision spectacles or contact lenses. More recently, it is reported that the children wearing orthok lens of smaller back optical zone diameter (BOZD) demonstrated a smaller axial elongation when compared to children wearing lens with larger BOZD. We aimed to explored the myopia efficacy and visual quality of ortho-k with different BOZD (5.0mm or 6.2mm).
This prospective study aimed to evaluate the efficacy of orthokeratology lenses with different back optical zone diameters (BOZD) in slowing axial elongation. Additionally, visual quality will be assessed through measurements of wavefront aberrations, contrast sensitivity, and subjective visual quality using a validated questionnaire. The study seeks to explore the effectiveness of various Ortho-K lens designs and the potential factors influencing their outcomes.
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| Experimental Group | Experimental | Myopic children who need OK lens treatment |
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| Control group | Active Comparator | Myopic children who need OK lens treatment |
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| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| Orthokeratology with 5.0mm back optical zone diameter | Device | The orthokeratology lenses used in this study were Double Reservoir Lenses (DRL) manufactured by Precilens (Creteil, France). The lenses feature a dual reverse-curve design with a back optic zone diameter (BOZD) of 5.0 mm. |
| Measure | Description | Time Frame |
|---|---|---|
| Changes in axial length | Axial length was measured with a biometer | The change of baseline and 1years |
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| Measure | Description | Time Frame |
|---|---|---|
| Change of visual quality | The visual quality questionnaire used in this study was adapted from the questionnaire developed by Tilia et al. The questionnaire comprises five categories with a total of nine questions, each accompanied by descriptive text and illustrative images to assist participants in providing their responses. Participants were asked to select the image corresponding to each question, and their responses were converted into numerical scores ranging from 1 to 10, where a score of 1 represents the poorest visual quality. |
Inclusion Criteria:
Exclusion Criteria:
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| Name | Affiliation | Role |
|---|---|---|
| Tianjin Eye Hospital | Tianjin Eye Hospital Opotometic Center | Principal Investigator |
| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| Tianjin Eye Hospital Opotometric Center | Tianjin | Tianjin Municipality | 300020 | China |
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| ID | Term |
|---|---|
| D009216 | Myopia |
| D012030 | Refractive Errors |
| ID | Term |
|---|---|
| D005128 | Eye Diseases |
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| Orthokeratology with a 6.2 mm back optical zone diameter | Device | The orthokeratology lenses used were Euclid lenses manufactured by Euclid Systems (Herndon, VA, USA). These lenses feature a four-zone, five-curve design with a back optic zone diameter (BOZD) of 6.2 mm. |
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| Follow-up evaluations were conducted at baseline, and at 1 day, 1 week, 1 month, 3 months, 6 months, and 12 months after lens wear. The differences from baseline were calculated for each follow-up period. |
| Change of wavefront aberrations | Wavefront aberration data for the eye were obtained using a Hartmann-Shack wavefront sensor (i.Profiler plus, Carl Zeiss Co., Aalen, Germany). The data were analyzed using Zernike polynomial decomposition to calculate the root mean square (RMS) values of total higher-order aberrations (HOAs), spherical aberration, coma aberration, trefoil, astigmatism, and fourth-order aberrations. | Follow-up evaluations were conducted at baseline, and at 1 day, 1 week, 1 month, 3 months, 6 months, and 12 months after lens wear. The differences from baseline were calculated for each follow-up period. |
| Change of contract sensitivity | Contrast sensitivity was assessed using the OPTEC 6500P contrast sensitivity tester (OPTEC 6500P, Stereo Optical Company, Inc., Chicago, USA) at five spatial frequencies: 1.5, 3, 6, 12, and 18 cycles/degree. The contrast sensitivity scores were expressed in logarithmic units (base 10) following a logarithmic transformation. | Follow-up evaluations were conducted at baseline, and at 1 week, 1 month, 3 months, and 12 months after lens wear. The differences from baseline were calculated for each follow-up period. |