¹Syntropic Medical, Clinical, Klosterneuburg, Austria, ²University of Sao Paulo Medical school, Interdisciplinary Neuromodulation Service, Sao Paulo, Brazil, ³Institute of Science and Technology Austria, Neuroimmunology, Klosterbneuburg, Austria, ⁴UT Southwestern Medical Center, Interventional Psychiatry, Dallas, United States

Background: Previous preclinical and healthy volunteer studies have demonstrated that flickering white light at 60 Hz induces neuroplasticity while being safe and well-tolerated. These results suggest a potential application of flickering light at 60 Hz for the treatment of neuropsychiatric conditions, including depression.

Aims & Objectives: The Lux study (NCT06922812) was a single-center, open-label, feasibility study aimed at evaluating the safety and tolerability of repeated 60 Hz light stimulation in individuals with mild to moderate major depressive disorder. Clinical improvement was investigated as an exploratory endpoint.

Method: The study was conducted at the University of São Paulo, Brazil, from May 2025 to January 2026. Participants were mild to moderate depression patients (HDRS17>8), currently experiencing a depressive episode but showing an insufficient response to an antidepressant (must have been in a stable regimen for at least six weeks at enrolment). History of epilepsy, migraine, and other psychiatric or neurological disorders, as well as any eye disease, were the main exclusion criteria. For this study, a prototype wearable headset, fitted with a stripe of LED lights controlled by a dedicated APP on a smartphone, was used. The effects of 60 Hz flickering light were investigated as an adjunct to current treatment. The protocol consisted of 30 min of stimulation per day, 5 days a week, for 2 weeks (total of 10 sessions), in the clinic, with a 2-week and 4-week follow-up. Safety endpoints (primary) included side effects (collected every day) and ophthalmological examination via OCT (at baseline and at last follow-up). Exploratory clinical improvement was measured as a change in scores from baseline at sessions 5, 10, and at the 2 follow-ups. The scales used were HDRS17, HAM-A, MADRS, and BDI as well as the Pittsburgh Sleep Quality Index (PSQI). Data were analyzed with 1-way ANOVA with Tukey´s posthoc, using Graphpad Prism and Python.

Results: The study enrolled a total of 29 patients (average age: 37.34 years ± 8.96, sex: 72.41% female; race: 82.76% caucasian, 6.90% asian, 10.34% black; mean HDRS17 at baseline 16.9 ± 2.97). One patient was excluded due to a misdiagnosis, and five dropped out during the trial due to personal reasons (unrelated to the stimulation), leaving a final n of 23. The stimulation was very well tolerated, and no serious adverse event has been reported during the study. No retinal alterations were measured via OCT and ophthalmological examination at follow-up. Preliminary analysis of efficacy endpoints revealed a significant decrease in HDRS17, MADRS, Ham-A, and BDI scales at sessions 5 and 10 as compared to baseline. The decrease remained largely stable at 2 weeks and 4 weeks of follow-up. Additional analysis of clinical results is ongoing.

Discussion & Conclusions: Two-week stimulation with 60 Hz flickering light is a safe and well tolerated intervention in a population with major depressive disorder. Further studies will be needed to establish the feasibility of at-home use and the effect on clinical symptoms.