Chronic Low-back PainNCT05956067
Chromatic Retinal Stimulation to Reduce Chronic Pain and Pain Sensitivity
A study testing Green Light stimulation, Equal Energy White stimulation and S-cone modulating white light in people with Chronic Low-back Pain and Chronic Pain, run by University of North Carolina, Chapel Hill at 1 site in United States.
Trial summary
Participants with chronic pain conditions including chronic low back pain and fibromyalgia may benefit from light stimuli presented to the retina to reduce chronic pain severity and pain sensitivity. Read more about this study
- Who is it for?
- Ages 18 to 65 years
- Conditions the study is for
- Chronic Low-back Pain, Chronic Pain, Fibromyalgia
- What is being tested?
- Green Light stimulation, Equal Energy White stimulation and S-cone modulating white light
- Type of treatment
- Medical device
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 20 participants
- Where
- 1 siteUnited States
- Study dates
- 25 Aug 2023to 9 Oct 2027
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 65 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Adults greater than or equal to 18 and less than or equal to 65.
- Individuals who have been diagnosed with fibromyalgia or chronic low back pain by their physician.
- Individuals who experience an average pain severity greater than 4/10 in intensity at baseline.
- Willingness to wear a battery-operated portable ganzfeld light stimulator device for 2 hours per day at the same time each day (ideally complete the light therapy session between 5 am-10 am each morning) for 5 days.
- Alert and oriented, and able to provide informed consent
- Ability to read and speak English to complete validated questionnaires.
Who cannot join
- Vision disorders or conditions resulting in severe vision impairment or blindness
- Individuals with self-report of color blindness
- Prisoner Status
- Pregnancy
- No other history or condition that would, in the investigator's judgment, indicate that the patient would very likely be non-compliant with the study or unsuitable for the study (e.g., might interfere with the study, confound interpretation, or endanger the patient).
- History of seizure disorder
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
United States1 site, 1 recruiting
- Recruiting
University Of North Carolina
Chapel Hill, North Carolina, 27517
Matthew C Mauck, MD PhD, 919-966-5136, matt_mauck@med.unc.edu
Matthew C Mauck, MD PhD
About this study
Participants with chronic pain conditions including chronic low back pain and fibromyalgia may benefit from light stimuli presented to the retina to reduce chronic pain severity and pain sensitivity. Participants will be recruited into this study and will be presented with one of three uniform light stimuli via a wide-field ganzfeld in three conditions to determine the retinal mechanisms that reduce pain. This work will lead to a greater understanding of retinal mechanisms that contribute to pain and will assist the design of future studies to harness the potential of light based pain therapies.
- Conditions
- Chronic Low-back Pain, Chronic Pain, Fibromyalgia
- Being tested
- Green Light stimulation, Equal Energy White stimulation, S-cone modulating white light
- Medical subject headings
- Chronic Pain, Fibromyalgia
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Green Light stimulationDevice
A portable battery-operated ganzfeld light display will be used to deliver green light for 2 hours per day for 5 consecutive days.
Equal Energy White stimulationDevice
A portable battery-operated ganzfeld light display will be used to deliver white light for 2 hours per day for 5 consecutive days.
S-cone modulating white lightDevice
A portable battery-operated ganzfeld light display will be used to deliver S-cone modulating light for 2 hours per day for 5 consecutive days.
| Study group | Role | What they receive |
|---|---|---|
| Equal energy white stimulus | Experimental | Equal energy white light at 500 lux. The International Commission on Illumination (CIE) coordinates of this light are (x=y=0.33), indicating that the stimulus appears uniformly white which means that the activation of each of the three classes of photoreceptors are equivalent, thus silencing any chromatic opponency. The stimulus will be delivered by a portable battery-operated ganzfeld light stimulation device for 2 hours per day for 5 consecutive days. Receives: Device: Equal Energy White stimulation |
| Green light stimulus | Experimental | Green light at 500 lux. Participants will view 545 nm green light delivered via a portable battery-operated ganzfeld light stimulation device for 2 hours per day for 5 consecutive days. Receives: Device: Green Light stimulation |
| S-cone modulating white light | Experimental | The S-cone modulating light stimulus will alternate between two light conditions at 500 lux that will activate the S-cones by about 100x differentially between the two conditions while maintaining the L- an M-cones at constant activation between the two alternating conditions using 427 nm versus 545 nm light. The stimulus will be delivered by a portable battery-operated ganzfeld light stimulation device for 2 hours per day for 5 consecutive days. Receives: Device: S-cone modulating white light |
What is being measured
The primary outcome is the main question the study is designed to answer.
Feasibility: Percent follow-up
Percent follow-up for 1 week baseline visit. Follow-up greater than 70% will be considered feasible.
Measured: 1 week
Feasibility: Percent of flash surveys completed
Percent of flash surveys completed during light stimulation period. 0% is the lowest and 100% is the highest. Higher percentages indicate greater percent of flash surveys completed.
Measured: 1 week
Feasibility: Self-reported light stimulation sessions completed
Self-reported light stimulation sessions completed by flash survey administered after each light stimulation session over the 5 day stimulation period. Number of sessions will be reported the minimum is 0 and the maximum is 5.
Measured: 1 week
Secondary outcomes (5)
Change in pain intensity after stimulation
Pain intensity measured by a 0-10 numeric rating scale for overall pain. 0 represents no pain, and 10 represents the worst pain imaginable.
Measured: Baseline, 1 week
Change in pressure pain threshold
Pressure Pain Threshold is the threshold in which pain is experienced in response to increasing force applied to the trapezius measured by a pressure algometer in kilograms of force per square centimeter (kgf/cm^2). The higher the value, the higher the threshold. The maximum is 10 kgf/cm^2 and minimum is 0.
Measured: Baseline, 1 week
Change in Conditioned Pain modulation
Conditioned Pain modulation magnitude will be calculated as the difference in mean pressure pain threshold (kgf/cm^2) measured prior to and during the conditioning stimulus (cold water bath), with increases in pressure pain threshold during conditioning interpreted as evidence of efficient endogenous pain inhibition.
Measured: Baseline, 1 week
Change in Temporal Summation
Temporal Summation. The investigators will evaluate temporal summation using a 40g Neuropen applied to the skin of the volar forearm and lumbar region, following a train of 10 identical stimuli (1 Hz). Participants will report retrospectively, the pain intensity of the 1st and 10th pinprick using a 0-10 numerical rating scale (NRS). 0 is the minimum and 10 is the maximum pain intensity that will be reported.
Measured: Baseline, 1 week
Change in activity measured with an accelerometer
Activity will be measured by an accelerometer. Average daily step count for the duration of the stimulus. Average non-sedentary time in minutes will able be determined over the stimulation period and compared to the data collected over the 1 week run-in period.
Measured: 1 week prior to baseline and 1 week during light stimulation
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted21 Jul 2023
- Study start25 Aug 2023
- Primary completion1 Oct 2027 (estimated)
- Study completion9 Oct 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Chronic Low-back PainStudies of the same condition, open and under way.
- More trials run by University of North Carolina, Chapel HillThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Enrolment
- 20 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University of North Carolina, Chapel Hill
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Matthew C Mauck, MD, PhD, Principal investigator, University of North Carolina, Chapel Hill
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05956067
- Sponsor's protocol ID
- 23-1301
- Status last verified
- Oct 2026
- First submitted
- 28 Jun 2023
- Last updated
- 2 Nov 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- Yes
- Individual data sharing
- Yes: Deidentified individual data that supports the results will be shared beginning 9 to 18 months following publication provided the investigator who proposes to use the data has approval from an Institutional Review Board (IRB), Independent Ethics Committee (IEC), or Research Ethics Board (REB), as applicable, and executes a data use/sharing agreement with the University of North Carolina.
Study at a glance
From the registry record, last updated by the sponsor on 2 Nov 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Chromatic Retinal Stimulation to Reduce Chronic Pain and Pain Sensitivity
- ClinicalTrials.gov ID
- NCT05956067
- Acronym / sponsor ID
- 23-1301
- Conditions
- Chronic Low-back Pain, Chronic Pain, Fibromyalgia
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 20 participants (estimated)
- Lead sponsor
- University of North Carolina, Chapel HillUniversity, hospital or other
- Study start
- 25 Aug 2023 (actual)
- Primary completion
- 1 Oct 2027 (estimated)
- Study completion
- 9 Oct 2027 (estimated)
- First posted
- 21 Jul 2023 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Participants with chronic pain conditions including chronic low back pain and fibromyalgia may benefit from light stimuli presented to the retina to reduce chronic pain severity and pain sensitivity. Participants will be recruited into this study and will be presented with one of three uniform light stimuli via a wide-field ganzfeld in three conditions to determine the retinal mechanisms that reduce pain. This work will lead to a greater understanding of retinal mechanisms that contribute to pain and will assist the design of future studies to harness the potential of light based pain therapies.
Study design
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| Equal energy white stimulus | Experimental | Device: Equal Energy White stimulationEqual energy white light at 500 lux. The International Commission on Illumination (CIE) coordinates of this light are (x=y=0.33), indicating that the stimulus appears uniformly white which means that the activation of each of the three classes of photoreceptors are equivalent, thus silencing any chromatic opponency. The stimulus will be delivered by a portable battery-operated ganzfeld light stimulation device for 2 hours per day for 5 consecutive days. |
| Green light stimulus | Experimental | Device: Green Light stimulationGreen light at 500 lux. Participants will view 545 nm green light delivered via a portable battery-operated ganzfeld light stimulation device for 2 hours per day for 5 consecutive days. |
| S-cone modulating white light | Experimental | Device: S-cone modulating white lightThe S-cone modulating light stimulus will alternate between two light conditions at 500 lux that will activate the S-cones by about 100x differentially between the two conditions while maintaining the L- an M-cones at constant activation between the two alternating conditions using 427 nm versus 545 nm light. The stimulus will be delivered by a portable battery-operated ganzfeld light stimulation device for 2 hours per day for 5 consecutive days. |
Who may qualify
- Ages
- 18 to 65 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (6 listed)
- Adults greater than or equal to 18 and less than or equal to 65.
- Individuals who have been diagnosed with fibromyalgia or chronic low back pain by their physician.
- Individuals who experience an average pain severity greater than 4/10 in intensity at baseline.
- Willingness to wear a battery-operated portable ganzfeld light stimulator device for 2 hours per day at the same time each day (ideally complete the light therapy session between 5 am-10 am each morning) for 5 days.
- Alert and oriented, and able to provide informed consent
Key exclusion criteria (6 listed)
- Vision disorders or conditions resulting in severe vision impairment or blindness
- Individuals with self-report of color blindness
- Prisoner Status
- Pregnancy
- No other history or condition that would, in the investigator's judgment, indicate that the patient would very likely be non-compliant with the study or unsuitable for the study (e.g., might interfere with the study, confound interpretation, or endanger the patient).
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Green Light stimulationA portable battery-operated ganzfeld light display will be used to deliver green light for 2 hours per day for 5 consecutive days. | Device | Green light stimulus |
| Equal Energy White stimulationA portable battery-operated ganzfeld light display will be used to deliver white light for 2 hours per day for 5 consecutive days. | Device | Equal energy white stimulus |
| S-cone modulating white lightA portable battery-operated ganzfeld light display will be used to deliver S-cone modulating light for 2 hours per day for 5 consecutive days. | Device | S-cone modulating white light |
Primary outcome
Feasibility: Percent follow-up
Time frame: 1 week
Percent follow-up for 1 week baseline visit. Follow-up greater than 70% will be considered feasible.
Feasibility: Percent of flash surveys completed
Time frame: 1 week
Percent of flash surveys completed during light stimulation period. 0% is the lowest and 100% is the highest. Higher percentages indicate greater percent of flash surveys completed.
Feasibility: Self-reported light stimulation sessions completed
Time frame: 1 week
Self-reported light stimulation sessions completed by flash survey administered after each light stimulation session over the 5 day stimulation period. Number of sessions will be reported the minimum is 0 and the maximum is 5.
5 secondary outcomes
Change in pain intensity after stimulation
Time frame: Baseline, 1 week
Change in pressure pain threshold
Time frame: Baseline, 1 week
Change in Conditioned Pain modulation
Time frame: Baseline, 1 week
Change in Temporal Summation
Time frame: Baseline, 1 week
Change in activity measured with an accelerometer
Time frame: 1 week prior to baseline and 1 week during light stimulation
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 2 Nov 2026.
- Individual participant dataSharing planned: Yes. Deidentified individual data that supports the results will be shared beginning 9 to 18 months following publication provided the investigator who proposes to use the data has approval from an Institutional Review Board (IRB), Independent Ethics Committee (IEC), or Research Ethics Board (REB), as applicable, and executes a data use/sharing agreement with the University of North Carolina.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Matthew C Mauck, MD, PhD principal investigator
University of North Carolina, Chapel Hill
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Green Light stimulation, Equal Energy White stimulation and S-cone modulating white light in people with Chronic Low-back Pain and Chronic Pain, run by University of North Carolina, Chapel Hill at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 6 inclusion and 6 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 2 Nov 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Matthew C Mauck, MD, PhD (919-966-5136, matt_mauck@med.unc.edu), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Feasibility: Percent follow-up (time frame: 1 week). The study lists 3 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 2 Nov 2026.