Repeated Low-Level Red-Light Therapy for Shortening Axial Length

Study Overview
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Brief Summary
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The purpose of this clinical trial is to confirm the incidence and magnitude of axial length shortening after RLRL therapy in Chinese high myopia children and teenagers.

Detailed Description
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High myopia has become a major public concern globally, which is characterized by excessive axial elongation of the eyeball. Axial elongation is accompanied by mechanical stretching and thinning of the choroid and sclera, causing vision-threatening complications. RLRL therapy is an emerging effective and safe therapy for myopia control. Previous clinical trials in China have observed clinically significant axial shortening after RLRL treatment. The purpose of this study is to confirm and identify possible mechanism for axial length (AL) shortening after 12-month RLRL therapy in Chinese highly myopic children and teenagers aged 6-16 years. In addition to single vision spectacles, subjects will receive RLRL treatment at home under supervision of the parents according to a standard protocol. Axial length, visual acuity, cycloplegic spherical equivalent refraction, intraocular pressure, slit lamp, optical coherence tomography, optical coherence tomography angiography and ultrawide-field optical coherence tomography will be measured at 1-, 3-, 6- and 12-month follow-up visits.

Official Title
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Repeated Low-Level Red-Light Therapy for Shortening Axial Length in Chinese High Myopia Children and Teenagers: a Prospective Single-Arm Study

Conditions
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High Myopia, Refractive Errors, Eye Diseases

Intervention / Treatment
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* Device: RLRL


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Provision of consent. Age: ≥ 6 and ≤ 16 years at enrolment. High myopia: cycloplegic sphere ≤ -6.00 diopters (D) in both eyes. Willing and able to participate in all required activities of the study. The children currently on myopia control treatment can be recruited if myopia control treatments (including but not limited to atropine, orthokeratology, rigid gas-permeable lenses, defocus spectacles, etc.) are discontinued for at least 2 weeks. Normal fundus, tessellated fundus or with peripapillary diffuse chorioretinal atrophy. Exclusion Criteria: Secondary myopia, such as a history of retinopathy of prematurity or neonatal problems, or syndromic myopia with a known genetic disease or connective tissue disorders, such as Stickler or Marfan syndrome. Pathologic myopia with signs of macula-involving diffuse chorioretinal atrophy, patchy chorioretinal atrophy, macular atrophy, lacquer cracks, myopic choroidal neovascularization or Fuchs' spots. Strabismus and binocular vision abnormalities in either eye. Previous any intraocular surgery affecting refractive status. Other reasons, including but not limited to ocular or other systemic abnormalities, that the physician may consider inappropriate for enrolment.

Ages Eligible for Study
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Minimum Age: 6 Years
Maximum Age: 16 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: RLRL therapy<br>In addition to SVS, participants will be treated with RLRL twice a school day. | Device: RLRL<br>* In addition to SVS with power for correcting distance refraction, RLRL will be performed twice per school day with an interval of at least 4 hours, each treatment last 3 minutes.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Incidence rate of axial length shortening >0.05 mm | Incidence rate of axial length shortening > 0.05 mm is characterized as the ratio of number of participants with axial length shortening greater than 0.05 mm to the total number. The IOL Master is used to measure axial length (mm). | 12 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Incidence rates of axial length shortening >0.10 mm and >0.20 mm | Incidence rate of axial length shortening > 0.10 mm and 0.20 mm are characterized as the ratio of number of participants with axial length hortening greater than 0.10 mm and 0.20 mm to the total number. The IOL Master is used to measure axial length (mm). | 12 months | 
| Magnitude of axial length shortening among shortened eyes | Magnitude of axial length shortening is characterized as the magnitude of axial length reduction among axial shortened eyes. The IOL Master is used to measure axial length (mm). | 12 months | 
| Changes in choroidal structural and perfusion parameters | Changes in choroidal structural and perfusion parameters are characterized as the difference between each follow-up visit and corresponding baseline values. Swept-source optical coherence tomography and optical coherence tomography angiography are used to measure choroidal structural and perfusion parameters. | 1, 3, 6 and 12 months | 
| Changes in retinal structures | Swept-source optical coherence tomography is used to measure retinal structures. | 1, 3, 6 and 12 months | 
| Changes in axial length and other biometric parameters | The IOL Master is used to measure axial length and other biometric parameters, including corneal curvature, anterior chamber depth and white to white, etc. Change of each parameter is characterized as the difference between each follow-up visit and baseline values | 1, 3, 6 and 12 months | 
| Change of cycloplegic spherical equivalent refraction (Diopter) | Cycloplegic spherical equivalent change (Diopter, D) is characterized as the difference between each follow-up visit and baseline values. Refraction with full cycloplegia is performed with an autorefractor. The data on spherical and cylindrical power and axis is automatically extracted from the autorefractor. The spherical equivalent power (D) is calculated as the spherical power (D) plus half of the cylindrical power (D) | 1, 3, 6 and 12 months | 
| Change of pathologic myopia fundus META-PM grading | The swept-source optical coherence tomography is used to obtain fundus images. The fundus images are classified based on META-PM classification system | 1, 3, 6 and 12 months | 
| Change in best corrected visual acuity | Best corrected visual acuity change is characterized as the difference between each follow-up visit and baseline values. An Early Treatment Diabetic Retinopathy Study chart with standard illumination at a distance of 4 meters is used to measure best corrected visual acuity | 1, 3, 6, and 12 months | 
| Incidence of self-reported adverse events | Incidence of self-reported adverse events is the rate of self-reported adverse events over a specified period for all the subjects. Subjects are asked to report any treatment-emergent adverse events, including but not limited to glare, flash blindness, and afterimages | 1, 3, 6 and 12 months |