Light Bulb Stimuli to Reduce Chronic Pain

This pilot, randomized, double-blind, crossover clinical trial is designed to evaluate the feasibility of administering a chromatic light intervention and to explore its effects on pain severity and pain sensitivity in adults with fibromyalgia or chronic widespread pain and fatigue. Following informed consent and enrollment, baseline assessments will be performed which will include demographic and health questionnaires, validated patient-reported outcome measures, and quantitative sensory testing (QST), including assessments of conditioned pain modulation, temporal summation, and pressure pain threshold. Participants will then be randomly assigned to one of two treatment sequences: S-cone stimulating chromatic light during Treatment Period 1 followed by equal-energy white light during Treatment Period 2. Equal-energy white light during Treatment Period 1 followed by S-cone stimulating chromatic light during Treatment Period 2. The study utilizes commercially available "TUO" programmable light bulbs that deliver pre-programmed light spectra. Participants will receive study equipment, including five programmed light bulbs, portable lamps, and an illuminometer to verify that the intervention light intensity is at least twice the ambient room illumination. Participants will use the assigned light condition for 2 hours daily, ideally between 5:00 a.m. and 10:00 a.m., for 7 consecutive days while engaging in normal daily activities. At the end of the first treatment period, participants will return for repeat patient-reported outcome assessments and quantitative sensory testing. Participants will then complete a 1-week washout period during which no light intervention is administered, although daily symptom surveys will continue. Following washout, participants will cross over to the alternate light condition and complete a second 7-day treatment period identical to the first. After completion of the second treatment period, participants will undergo final intervention assessments, return study equipment, and enter a 1-week follow-up period with continued daily symptom monitoring. At the final study visit, participants will complete follow-up questionnaires and optional quantitative sensory testing. The primary objective is to determine the feasibility and acceptability of delivering chromatic light therapy for 2 hours daily across two treatment periods. Secondary objectives include evaluating whether chromatic light exposure reduces chronic pain severity and pain sensitivity to a greater extent than an equal-energy white light control condition. Approximately 40 participants will be enrolled, and total participation time will be approximately 35 days. Risks associated with the intervention are expected to be minimal and primarily include potential light sensitivity or discomfort and standard risks related to data confidentiality.