Green Light-Based Analgesia - Novel Nonpharmacological Approach to Fibromyalgia Pain: A Pilot Study

There continues to be significant reliance on pharmacological modalities for the management of chronic pain, with a particular focus on opioid analgesics as a singular option for pain management. Fibromyalgia is a prototypical central pain disorder, which is often used as a model to study chronic pain disorders. It has an estimated prevalence of approximately 1.1% to 5.4% in the general population. The widespread use of opioids in patients with fibromyalgia has been well demonstrated in several health claims database studies, with rates of use ranging from 11.3% to 69%. Minimizing opioid exposures reduces misuse risk, but requires adequate opioid-sparing multimodal analgesic strategies, particularly nonopioid analgesic adjuncts, to ensure effective treatment of pain, particularly high-impact pain. We chose fibromyalgia as our study population. Given that it is a disordered sensory processing condition, it may be particularly amenable to the beneficial effects of green-light therapy.

Most studies have evaluated exposure to light-emitting diode lights as a mode of green-light delivery; our study used green-light filtering eyeglasses, which would allow the wearer to move about with minimal interference.

We conducted a randomized controlled trial to test the feasibility of green-light filtering eyeglasses in the treatment of chronic pain.

This study was conducted at Duke University Health System.

We recruited and randomized adult patients with a known diagnosis of fibromyalgia patients and excluded patients who were unable to wear eyeglasses for at least 4 hours per day or were colorblind according to the Ishihara Colorblindness Test. Patients were assigned to 1 of 3 arms: clear eyeglasses (control), green eyeglasses, or blue eyeglasses. We initially recruited 45 patients and randomly assigned 15 patients per group.

To evaluate clinical significance, we determined the rate of >= 10% decline in oral morphine equivalents and found that 33%, 11%, and 8% of the green, blue, and clear eyeglass groups, respectively, achieved this clinically meaningful outcome.

This study was powered to detect feasibility of the intervention, rather than conclusive analgesic effects.

Our study demonstrated the feasibility of this treatment approach and study design and supports a future study to determine the efficacy of green light-based analgesia on opioid use, pain, and anxiety. While the reduction of opioid use was not of statistical significance, we believe it to be of clinical significance as there was no increase of patient-reported pain. This warrants further investigation in a large-scale trial of the use of green-light filtration of ambient light to mitigate opioid use and possible mediation of psychological impacts of pain with the use of green-lensed eyeglasses.