LED Red Light in Modulating Choroidal Microcirculation to Retard Retinal Atrophy in Pathological Myopia

Pathological myopia (PM) is a major cause of irreversible visual impairment and blindness in adults, characterized by progressive axial elongation, choroidal thinning, impaired choroidal microcirculation, and subsequent retinal atrophy, which currently lacks effective therapeutic interventions. Against this clinical backdrop, this prospective randomized controlled trial is designed to systematically investigate the therapeutic efficacy and safety of LED repeated low-level red light (RLRL) therapy in adult patients with PM. The core research objectives are twofold: first, to verify whether LED-RLRL can modulate choroidal microcirculatory function and thereby retard the progression of retinal atrophy in PM patients, and second, to comprehensively assess the safety profile of long-term LED-RLRL administration by monitoring adverse events. To achieve these goals, the study will adopt a randomized controlled design, where eligible participants will be randomly assigned to either the active treatment group or the sham control group. The active treatment group will receive LED-RLRL therapy, while the control group will be administered interventions using a sham device-this device is identical in appearance and operation mode to the active LED-RLRL device but has an energy output of less than 10% of the original, aiming to exclude the placebo effect. The intervention regimen for both groups is standardized: participants will receive the assigned intervention twice daily, with each session lasting 3 minutes, 5 days per week, for a continuous 12-month course. During the study period, all participants will undergo regular follow-up visits at the clinic every 3 months, where a series of comprehensive assessments will be performed, including but not limited to visual acuity measurement, fundus examination, optical coherence tomography (OCT) for choroidal thickness and retinal structure evaluation, and choroidal blood flow dynamic detection to quantify microcirculatory changes. Additionally, participants will be instructed to maintain a detailed daily diary, recording the occurrence time, duration, and severity of any subjective symptoms (e.g., eye fatigue, photophobia) as well as changes in visual perception (e.g., contrast sensitivity, visual field changes), which will serve as supplementary data for safety monitoring and efficacy evaluation. Collectively, this study is expected to provide high-quality evidence for the clinical application of LED-RLRL in the management of PM by clarifying its regulatory effect on choroidal microcirculation and its role in delaying retinal atrophy, while defining its safety boundaries.

Inclusion criteria

• Age range: 18 to 55 years old;
• Baseline visual acuity: Best Corrected Visual Acuity (BCVA) ≥ 0.1 (LogMAR ≤ 1.0);
• Meeting the diagnostic criteria for high myopia: Spherical Equivalent (SE) ≤ -6.00 D and Axial Length (AL) ≥ 26.0 mm;
• Meeting one of the following pathological fundus changes:

(i) Fundus manifestations corresponding to Category 2 (diffuse chorioretinal atrophy), Category 3 (patchy chorioretinal atrophy), or Category 4 (macular atrophy associated with choroidal neovascularization) of the META-PM classification criteria*; (ii) Category 1 of the META-PM classification criteria* complicated with macular schisis; (iii) BCVA < 0.6;

Exclusion criteria

• Concurrent with other ophthalmic diseases that may affect visual acuity or outcome assessment, including active myopic choroidal neovascularization (CNV) requiring anti-VEGF therapy, macular hole, vitreous hemorrhage, diabetic retinopathy, retinal detachment, retinal vein occlusion, optic neuritis, uveitis, severe cataract, and glaucoma;
• Systemic contraindications: Photosensitive epilepsy, autoimmune diseases (e.g., systemic lupus erythematosus), or pregnant/lactating women; Patients who have undergone intraocular surgery, laser treatment, or ophthalmic medication therapy within 3 months prior to enrollment;
• Patients unable to comply with regular follow-up (e.g., due to remote residence) or with cognitive impairment;
• Opaque refractive media that hinder fundus examination.