PainNCT07033949
Effect of Green Light Exposure at Different Times on the Pain of Subjects
A study testing Green light glasses in people with Pain, run by The Second Affiliated Hospital of Chongqing Medical University at 1 site in China.
Trial summary
This study investigated the effects of green-light exposure on pain sensitivity in healthy volunteers and on perioperative pain in surgical patients. Healthy volunteers underwent 30-min green-light exposure at three different times of day (08:00-09:00, 12:00-13:00, and 16:00-17:00) on separate days using a… Read more about this study
- Who is it for?
- Ages 18 to 65 yearsHealthy volunteers can take part
- Conditions the study is for
- Pain
- What is being tested?
- Green light glasses
- Type of treatment
- Medical device
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 140 participants
- Where
- 1 siteChina
- Study dates
- 1 Jul 2025to 6 Apr 2026
- Phase
- Interventional
- Are there results?
- None posted in the registry
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
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Healthy volunteers:
- Age 18-65 years.
- ASA physical status I.
- 1. Age 18-65 years. 2. ASA physical status I-III. 3. Scheduled for elective abdominal surgery under general anesthesia requiring arterial puncture.
Who cannot join
- Skin ulceration, dermatitis, or allergic reactions at the study site.
- Chronic use of analgesics or psychiatric medications.
- Color blindness or uncorrected cataracts.
- Severe cardiovascular, respiratory, or inflammatory diseases.
- Failure of the initial arterial puncture attempt (surgical cohort only).
- Inability to communicate or provide informed consent.
Trial locations and contacts
1 site in 1 country.
China1 site
The Second Affiliated Hospital of Chongqing Medical University
Chongqing, Chongqing Municipality, 4000000
About this study
Official title: A Randomized Controlled Study on the Effect of Green Light Exposure at Different Times on the Pain of Subjects
This study investigated the effects of green-light exposure on pain sensitivity in healthy volunteers and on perioperative pain in surgical patients. Healthy volunteers underwent 30-min green-light exposure at three different times of day (08:00-09:00, 12:00-13:00, and 16:00-17:00) on separate days using a within-subject design, with a washout period of at least 2 days between sessions. Surgical patients undergoing elective surgery under general anesthesia with preoperative arterial puncture were randomly assigned in a 1:1 ratio to either a green-light intervention group or a sham-device control group. The assigned intervention was initiated before arterial puncture and continued throughout surgery. The effects of green-light exposure on pain sensitivity, procedural pain, and perioperative pain were evaluated.
Read the detailed description
The study consisted of two components. In the healthy-volunteer component, participants underwent a 30-min green-light exposure at three different times of day (08:00-09:00, 12:00-13:00, and 16:00-17:00) on separate days in a within-subject design, with a washout period of at least 2 days between sessions. Pain threshold, pain tolerance, and cold pain sensitivity were assessed before and after each exposure.
In the surgical component, eligible patients were randomly assigned in a 1:1 ratio to either the green-light intervention group or the sham-device control group using a computer-generated random sequence. Participants wore identical wearable GLED glasses for 30 min before arterial puncture and throughout surgery. In the intervention group, the device delivered 511-515 nm green light at 100 lux; in the control group, the device remained powered off and participants were exposed only to ambient room light. Care providers, investigators not involved in intervention administration, and clinical outcome assessors were blinded to group allocation. Personnel responsible for device allocation and administration were unblinded and were not involved in perioperative clinical care or outcome assessment.
- Conditions
- Pain
- Being tested
- Green light glasses, Sham GLED glasses
- Keywords
- Acute Pain, Green light
- Medical subject headings
- Pain, Acute Pain
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Green light glassesDevice
Exposure to green light for 30 minutes and during the surgery.
Sham GLED glassesDevice
Identical GLED glasses remained powered off for 30 min before arterial puncture and throughout surgery.
| Study group | Role | What they receive |
|---|---|---|
| Green light exposure group | Experimental | Participants wore GLED light-therapy glasses delivering 511-515 nm green light at 100 lux for 30 min before arterial puncture and throughout surgery. Receives: Device: Green light glasses |
| Sham-device control group | Sham comparator | Participants wore identical GLED light-therapy glasses for 30 min before arterial puncture and throughout surgery. The device remained powered off, and participants were exposed only to ambient room light. Receives: Device: Sham GLED glasses |
What is being measured
The primary outcome is the main question the study is designed to answer.
Pain intensity during arterial puncture
Numeric Rating Scale (NRS), ranging from 0 to 10, with higher scores indicating greater pain intensity.
Measured: The pain score during arterial puncture
Secondary outcomes (4)
Pain sensitivity
Pain sensitivity was assessed using pressure pain threshold and pressure pain tolerance measured with an algometer. In healthy volunteers, cold pain sensitivity was additionally assessed using a cold test.
Measured: Immediately before and 30 minutes after light exposure
Analgesic consumption during surgery
assessed by the actual dose of analgesic during the surgery
Measured: From surgery beginning to the ending of the surgery
Pain intensity after surgery
Numeric Rating Scale (NRS), ranging from 0 to 10, with higher scores indicating greater pain intensity.
Measured: From ending of the surgery to 24 hours after surgery
Analgesic consumption after surgery
assessed by the actual dose of analgesic after surgery
Measured: From ending of the surgery to 24 hours after surgery
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted24 Jun 2025
- Study start1 Jul 2025
- Primary completion4 Apr 2026
- Study completion6 Apr 2026
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for PainStudies of the same condition, open and under way.
- 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
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind
- Who is masked
- Care provider, Investigator, Outcomes assessor
- Enrolment
- 140 participants (actual)
Sponsor and investigators
- Lead sponsor
- The Second Affiliated Hospital of Chongqing Medical University
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Guangyou Duan, Principal investigator, The Second Affiliated Hospital, Chongqing Medical University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07033949
- Sponsor's protocol ID
- GLE
- Status last verified
- Sep 2026
- First submitted
- 15 Jun 2025
- Last updated
- 17 Sep 2026
- Results posted
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 17 Sep 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Randomized Controlled Study on the Effect of Green Light Exposure at Different Times on the Pain of Subjects
- ClinicalTrials.gov ID
- NCT07033949
- Acronym / sponsor ID
- GLE
- Conditions
- Pain
- Keywords
- Acute Pain, Green light
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 140 participants (actual)
- Lead sponsor
- The Second Affiliated Hospital of Chongqing Medical UniversityUniversity, hospital or other
- Study start
- 1 Jul 2025 (actual)
- Primary completion
- 4 Apr 2026 (actual)
- Study completion
- 6 Apr 2026 (actual)
- First posted
- 24 Jun 2025 (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.
This study investigated the effects of green-light exposure on pain sensitivity in healthy volunteers and on perioperative pain in surgical patients. Healthy volunteers underwent 30-min green-light exposure at three different times of day (08:00-09:00, 12:00-13:00, and 16:00-17:00) on separate days using a within-subject design, with a washout period of at least 2 days between sessions. Surgical patients undergoing elective surgery under general anesthesia with preoperative arterial puncture were randomly assigned in a 1:1 ratio to either a green-light intervention group or a sham-device control group. The assigned intervention was initiated before arterial puncture and continued throughout surgery. The effects of green-light exposure on pain sensitivity, procedural pain, and perioperative pain were evaluated.
Detailed description
The study consisted of two components. In the healthy-volunteer component, participants underwent a 30-min green-light exposure at three different times of day (08:00-09:00, 12:00-13:00, and 16:00-17:00) on separate days in a within-subject design, with a washout period of at least 2 days between sessions. Pain threshold, pain tolerance, and cold pain sensitivity were assessed before and after each exposure.
In the surgical component, eligible patients were randomly assigned in a 1:1 ratio to either the green-light intervention group or the sham-device control group using a computer-generated random sequence. Participants wore identical wearable GLED glasses for 30 min before arterial puncture and throughout surgery. In the intervention group, the device delivered 511-515 nm green light at 100 lux; in the control group, the device remained powered off and participants were exposed only to ambient room light. Care providers, investigators not involved in intervention administration, and clinical outcome assessors were blinded to group allocation. Personnel responsible for device allocation and administration were unblinded and were not involved in perioperative clinical care or outcome assessment.
Study design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind (care provider, investigator, outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Green light exposure group | Experimental | Device: Green light glassesParticipants wore GLED light-therapy glasses delivering 511-515 nm green light at 100 lux for 30 min before arterial puncture and throughout surgery. |
| Sham-device control group | Sham comparator | Device: Sham GLED glassesParticipants wore identical GLED light-therapy glasses for 30 min before arterial puncture and throughout surgery. The device remained powered off, and participants were exposed only to ambient room light. |
Who may qualify
- Ages
- 18 to 65 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (4 listed)
- Age 18-65 years.
- ASA physical status I.
- 1. Age 18-65 years. 2. ASA physical status I-III. 3. Scheduled for elective abdominal surgery under general anesthesia requiring arterial puncture.
Key exclusion criteria (6 listed)
- Skin ulceration, dermatitis, or allergic reactions at the study site.
- Chronic use of analgesics or psychiatric medications.
- Color blindness or uncorrected cataracts.
- Severe cardiovascular, respiratory, or inflammatory diseases.
- Failure of the initial arterial puncture attempt (surgical cohort only).
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 glassesExposure to green light for 30 minutes and during the surgery. | Device | Green light exposure group |
| Sham GLED glassesIdentical GLED glasses remained powered off for 30 min before arterial puncture and throughout surgery. | Device | Sham-device control group |
Primary outcome
Pain intensity during arterial puncture
Time frame: The pain score during arterial puncture
Numeric Rating Scale (NRS), ranging from 0 to 10, with higher scores indicating greater pain intensity.
4 secondary outcomes
Pain sensitivity
Time frame: Immediately before and 30 minutes after light exposure
Analgesic consumption during surgery
Time frame: From surgery beginning to the ending of the surgery
Pain intensity after surgery
Time frame: From ending of the surgery to 24 hours after surgery
Analgesic consumption after surgery
Time frame: From ending of the surgery to 24 hours after surgery
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 17 Sep 2026.
Related trials for Pain
Not yet recruiting
Effect of Stress Ball Use During Femoral Arterial Sheath Removal After Coronary Angiography
Femoral Arterial Sheath Removal, Stress Ball
Recruiting
Empowered Relief® for Cancer Survivors With Chronic Pain
Chronic Pain Due to Cancer, Pain Catastrophizing
RecruitingPhase 4
ESP Blocks for Posterior Spinal Fusion
Postoperative Pain
RecruitingObservational study
Pain Phenotypes in Individuals With Multiple Sclerosis
Multiple Sclerosis, Chronic Pain
Not yet recruiting
Effects of Hip Hinge Exercises on Pain, Range of Motion and Functional Disability in Non-specific Low Back Pain.
Low Back Pain
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. This study is not recruiting at the moment.
Guangyou Duan principal investigator
The Second Affiliated Hospital, Chongqing Medical University
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 glasses in people with Pain, run by The Second Affiliated Hospital of Chongqing Medical University at 1 site in China.
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 4 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: finished, as of the sponsor's last update on 17 Sep 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 China. 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. Some participants in this study may receive a placebo. 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?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Pain intensity during arterial puncture (time frame: The pain score during arterial puncture). 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 17 Sep 2026; AzTrials last refreshed its copy on 7 Nov 2026.