Elucidating the Central Mechanisms of Action for Green Light Therapy in Managing Chronic Pain

After a patient is consented, investigators will collect the baseline Fibromyalgia Impact Questionnaire survey (FIQ), thermal and mechanical pain detection and tolerance threshold, conditioned pain modulation (CPM), collect cerebrospinal fluid (CSF), and obtain positron emission tomography scan (PET scan) for microglia baseline activity. It is expected that the PET scan will take place on different day given the time needed and preparation for the completion of a PET scan. Investigators expect the baseline value collections to take 1-2 days to complete. Once all baseline values are obtained, the light therapy exposure will begin. The start of light exposure will be considered the start of Week 1. Investigators will follow up with the patient over the phone every 2 weeks +/- 1 week to ensure safety and compliance and to answer any questions the patient may have. Recruited patients will also have investigator's contact information to contact investigators with any urgent questions. At the end of Week 10, investigators will obtain the final values for the FIQ survey, thermal and mechanical pain detection and tolerance threshold, CPM, collect CSF, and obtain PET scan.

Inclusion criteria

• 18 years or older who can speak and understand English
• Meets the diagnostic criteria for fibromyalgia accroding to the 2016 revisions to the 2010/2011 fibromyalgia diagnostic criteria.
• Average numeric pain score of 5 out of 10 or greater over the 10 weeks prior to enrolling in the study, and failure of medical therapy to control their pain.

Exclusion criteria

• Serious mental illness defined as distortions of perception, delusions, hallucinations, and unusual behaviors resulting in loss of contact with reality. This will be assessed during the screening interview. Patients with psychiatric disorders will have their medical record reviewed prior to enrollment
• History of color blindness or uncorrected cataracts
• Subjects receiving remuneration for their medical condition.
• Genotype of low affinity binders for translocator protein, (TSPO), as patients with low affinity binding TSPO may not have adequate uptake for the radioactive tracer used for the PET scan.