To explore the minimum power and frequency of Repeated Low-level Red-light (RLRL) to control myopia progression in low-myopic children aged 8-10 years, and the rebound effect of low-myopic children after discontinuation of RLRL with different combinations of power and frequency.

Myopia has emerged as a significant public health concern in East Asia. The excessive elongation of the axial length ( AL)of the eye, particularly as myopia progresses to high myopia, is associated with mechanical stretching and thinning of the choroid and sclera. This can lead to vision-threatening complications such as myopic macular degeneration, macular hemorrhage, retinal detachment, cataracts, and glaucoma. Given the serious consequences of high myopia and its associated complications, early and effective prevention and control of myopia become a primary focus in safeguarding visual health and enhancing quality of life.

In recent years, RLRL holds significant potential as an effective strategy for preventing and controlling myopia in children and adolescents. However, recent researches prompt further questions: Is the current power of RLRL exposure optimal? Can the frequency of exposure be refined? What is the relationship among exposure power, frequency and myopia control? To explore these questions and clarify the effects of various combinations of exposure power and frequency on myopia progression following RLRL therapy, our research group plans to conduct a prospective, double-blind, single-center, randomized controlled clinical trial. This study aims to provide more comprehensive evidence to support this innovative intervention on myopia prevention and control.

Inclusion Criteria:

1. Age: 8-10 years old
2. Low myopia: cycloplegic spherical equivalent refractions (SERs) range from -0.50 (inclusive) to -3.00 diopters (D) and astigmatism less than -2.5 D in either eye.
3. signed informed consent and was able to participate in the study

Exclusion Criteria:

1. Secondary myopia, such as a history of retinopathy of prematurity or other neonatal diseases; syndromic myopia with a known genetic disorder or connective tissue disease, such as Stickler syndrome or Marfan syndrome
2. Strabismus or other binocular vision abnormalities
3. Cloudy refractive media: cloudy cornea, cataract or intraocular lens surgery
4. Eye diseases that affect retinal function: macular degeneration, diabetic retinopathy, retinal detachment, glaucoma or ocular hypertension, endophthalmitis, uveitis, optic neuropathy, etc.
5. History of refractive surgery, internal eye surgery, laser therapy, vitreous injection, etc.
6. diabetes, hypertension and other systemic disorders
7. History of use of retinal toxic drugs, such as hydroxychloroquine, etc.
8. Use of orthokeratology, atropine, multifocal frame glasses and other myopia control methods; children who are currently receiving atropine, orthokeratology, multifocal frame glasses and other myopia control treatment, can be enrolled after 2 weeks of treatment.
9. Other reasons considered unsuitable for inclusion by the study physician, including but not limited to other ocular and systemic disease abnormalities

Data will be shared as open data after proper anonymization.