This clinical trial aims to exploratively compare and evaluate the structural changes in the eye (specifically changes in choroidal thickness) pre- and post-treatment of the investigational medical devices ('SAT-001' and 'modified SAT-001') in pediatric myopia patients, and the differences in their effects on the eye.

Myopia is a rapidly growing global concern, particularly in pediatric populations, with high rates of progression and the potential for serious long-term consequences. The risk of developing high myopia, which can lead to complications such as retinal detachment, cataracts, glaucoma, and optic nerve abnormalities, underscores the importance of effective management strategies for pediatric myopia. While treatments to slow myopia progression have been explored, including pharmacological and non-pharmacological approaches, further investigation is needed into their long-term safety and efficacy.

This multicenter, randomized, open-label, parallel-group, exploratory clinical trial aims to evaluate the impact of SAT-001, a Software as a Medical Device (SaMD), on choroidal thickness in pediatric patients. The study will compare changes in choroidal thickness between two groups: one receiving SAT-001 and the other receiving mSAT-001, a modified version of SAT-001 that excludes the rest period during device use. Participants will be assessed before and after a single application of the device.

Inclusion Criteria:

1. Children aged 4 to 12

2. Meet the following refractive criteria by cycloplegic refraction

   1. Spherical equivalent refractive error (SER): -0.75 to less than -6.00 D in both eyes
   2. Astigmatism of 2.50 D or less in both eyes

3. Best corrected visual acuity of 0.2 logMAR or better in each eye at the Screening Visit

4. Gestational age of 38 weeks or more at birth, or birth weight of 2,500g or more

5. Transparent ocular media

6. Participants and their legal guardians who agree to participate in the clinical trial and are willing to provide signed informed consent after receiving and understanding the explanation of the trial description (participants under 6 years old may mark their agreement after receiving full information and understanding)

Exclusion Criteria:

1. History of eye diseases such as manifest strabismus, intermittent strabismus, amblyopia, and nystagmus (excluding strabismus that maintains binocular vision)
2. History of ocular surgery such as eyelid surgery, strabismus surgery, intraocular surgery, or refractive correction surgery (excluding simple double eyelid surgery)
3. Ocular abnormalities in cornea, lens, central retina, iris, ciliary body, etc., or presence of malignant tumors in the orbital area
4. History of multifocal lenses (e.g., progressive lenses), corneal refractive therapy lenses (Ortho-K, e.g., Dream lenses), rigid gas permeable (RGP) hard lenses, defocus incorporated multiple segments (DIMS) spectacle lenses (e.g., MyoSmart) within 30 days prior to Visit 2.
5. History of using myopia control agents (e.g., atropine) within 30 days prior to Visit 2
6. Currently participating in another clinical trial or who have participated in another clinical trial within 3 months prior to screening (Visit 1)
7. Inappropriate at the discretion of the investigator due to potential ethical concerns or the possibility of affecting the clinical trial results