Repeated Low-Level Red-Light Therapy in Dry Age-Related Macular Degeneration

Safety and Efficacy of Repeated Low-Level Red-Light Therapy in Dry Age-Related Macular Degeneration: A Randomized Controlled Trial

This prospective, double-blind, randomized controlled trial aims to evaluate the efficacy and safety of repeated low-level red-light (RLRL) therapy in patients with dry age-related macular degeneration (AMD). The primary objective is to assess the effect of RLRL therapy on visual function in patients with dry AMD, while the secondary objective is to evaluate its safety and tolerability.

Seventy-four participants aged 50 years or older with dry AMD will be enrolled and randomly assigned in a 1:1 ratio to either the active RLRL intervention group (using the full device power) or the control group (sham device at 10% power). Group assignments will be masked to both participants and investigators. Participants will administer the treatment at home twice daily (3-minute sessions, with at least a 4-hour interval between sessions) over five consecutive weekdays each month for three months. A video tutorial will guide device usage, with ongoing support from the research team.

Before enrollment, participants will undergo a comprehensive assessment, including ocular and family history review, OCT, and fundus photography to confirm eligibility. Evaluations will occur at baseline, 1 month, and 3 months, covering best-corrected visual acuity (BCVA), slit-lamp examination, OCT, OCT angiography (OCTA), fundus autofluorescence (FAF), contrast sensitivity, color vision, electroretinography (ERG), visual-related quality of life (VRQL) questionnaires, and adverse event monitoring.

The primary outcome is the mean change in BCVA from baseline to 3 months. Secondary outcomes include changes in central drusen thickness, geographic atrophy (GA) size and progression, choroidal blood flow, contrast sensitivity, ERG responses, and VRQL scores.

Given the limited treatment options for dry AMD, which are primarily focused on lifestyle changes and nutritional supplements, this study investigates the potential of RLRL therapy as a novel, non-invasive treatment. The results may address the unmet medical need in dry AMD, potentially slowing disease progression and improving patients' quality of life.

Inclusion Criteria:

1. Age ≥ 50 years old.

2. Diagnosis of dry AMD in Age-Related Eye Disease Study (AREDS) category 2 to 4, as determined by color fundus photography and fundus autofluorescence imaging. The AREDS categories will be defined as follows:

   i) AREDS category 2 (early AMD): Multiple small drusen, a few intermediate drusen (63-124 μm in diameter), or retinal pigment epithelium (RPE) abnormalities ii) AREDS category 3 (intermediate AMD): Extensive intermediate drusen, including at least one large drusen (> 125 μm in diameter), or geographic atrophy (GA) not involving the center of the fovea.

   iii) AREDS category 4 (advanced/late AMD): GA involving the center of the macula.

   If both eyes meet the inclusion criteria, both eyes will be included in the study analysis.

3. ETDRS BCVA score between 50 and 75 (Snellen equivalent of 20/32 to 20/100). Willingness to provide written informed consent after being informed of the nature of the study.

Exclusion Criteria:

1. Previous or active neovascular maculopathy.
2. Presence of center involving GA within the central 500 μm of the ETDRS grid.
3. Ocular disease other than dry AMD that could cause drusen (glomerulonephritis Type 2, Autosomal dominant drusen), GA (North Carolina macular dystrophy), or mitochondrial disorders (parafoveal petaloid GA, Stargardt disease).
4. Invasive eye surgery (e.g. cataract extraction, capsulotomy) within 3 months.
5. Cognitive impairment or history of epilepsy.
6. Other significant ocular disease affecting visual acuity (e.g., diabetic macular edema, uncontrolled glaucoma, active uveitis, vitreoretinal disease, intraocular tumor, retinal vascular disease, lens opacities more severe than C2, N2, P2 [LOCS III]).

Afterimage > 5 min (contraindication of red-light therapy).