Visual FatigueNCT07706231
A Study of Full-Spectrum Screen Lighting for Reducing Screen-Related Eye Fatigue and Dry Eye
A study testing Full-spectrum screen bar light and Brightness-matched screen task without screen bar lighting in people with Visual Fatigue and Dry Eye, run by Zhongshan Ophthalmic Center, Sun Yat-sen University at 1 site in China.
Trial summary
This study will evaluate whether full-spectrum screen bar lighting can reduce eye fatigue and dry eye symptoms after a standardized screen task. Prolonged screen use is common in daily work and study and may cause blurred vision, eye soreness, dryness, headache, and reduced attention. Read more about this study
- Who is it for?
- Ages 18 to 35 yearsHealthy volunteers can take part
- Conditions the study is for
- Visual Fatigue, Dry Eye, Computer Vision Syndrome
- What is being tested?
- Full-spectrum screen bar light and Brightness-matched screen task without screen bar lighting
- Type of treatment
- Medical device
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 112 participants
- Where
- 1 siteChina
- Study dates
- 22 Sep 2026to 1 Apr 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 35 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Age 18 to 35 years, male or female.
- Average daily electronic screen exposure of at least 4 hours.
- Near visual acuity at 40 cm of 0.5 or better, and able to complete the study 1. tasks and measurements stably.
- Able and willing to provide written informed consent.
Who cannot join
- Presence of ocular inflammation or ocular disease.
- History of severe systemic disease, neurological disease, or psychiatric disorder.
- Use of dry eye or visual fatigue treatments, or contact lens wear, within 1 month before the study.
- History of ocular surgery within the past 6 months.
- Daily use of lenses with blue-light blocking, photochromic, polarized, filtering, or similar optical functions.
- Professional background in ophthalmology or optical products.
Show all 12Show fewer
- Intake of caffeine or other stimulants within 4 hours before the study.
- Best-corrected visual acuity (BCVA) less than 0.8.
- Anisometropia of 1.00 diopter or greater, or astigmatism of ±2.00 diopters or greater.
- Intraocular pressure (IOP) less than 5 mmHg or greater than 21 mmHg.
- Non-invasive tear breakup time (NIBUT) less than 5 seconds in either eye.
- Ocular Surface Disease Index (OSDI) score of 33 or greater.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
About this study
Official title: A Randomized Controlled Trial of the Effects of Full-Spectrum Screen Bar Lighting on Visual Fatigue and Dry Eye After a Standardized Screen Task
This study will evaluate whether full-spectrum screen bar lighting can reduce eye fatigue and dry eye symptoms after a standardized screen task. Prolonged screen use is common in daily work and study and may cause blurred vision, eye soreness, dryness, headache, and reduced attention. Light environment may be one way to improve visual comfort during screen use, but more controlled clinical evidence is needed.
In this randomized, parallel-group controlled study, 112 healthy adult participants will be assigned to either a full-spectrum screen bar lighting group or a brightness-matched control group without screen bar lighting. Participants in both groups will complete an approximately 2-hour standardized screen task in a controlled laboratory environment. The study will compare changes before and after the task in objective and subjective measures of visual fatigue and dry eye, including critical flicker fusion frequency, visual fatigue questionnaire scores, eye movement and blinking parameters, pupil parameters, tear film-related measurements, and dry eye symptom scores. Safety and discomfort during the study will also be recorded.
Read the detailed description
Prolonged use of electronic screens is increasingly common in work, study, and daily life and may lead to visual fatigue and dry eye-related symptoms. These symptoms may include blurred vision, eye soreness, dryness, headache, and reduced attention. Although behavioral strategies such as taking breaks and adjusting viewing distance are commonly recommended, their effectiveness may be limited by individual adherence. Optimizing the lighting environment during screen use may provide a standardized and practical approach to improving visual comfort.
This is a single-center, randomized, parallel-group controlled study designed to evaluate the effects of full-spectrum screen bar lighting during a standardized screen task. Eligible healthy adult participants with regular daily screen exposure will be randomly assigned in a 1:1 ratio to either a full-spectrum screen bar lighting group or a brightness-matched control group without screen bar lighting. Both groups will complete the same approximately 2-hour standardized screen task in a controlled laboratory environment. The task may include computer-based text processing, screen reading, or viewing specified video materials, with the task content, duration, and completion requirements kept consistent between groups.
Assessments will be performed before and immediately after the standardized screen task. The study will evaluate changes in objective and subjective measures of visual fatigue, ocular behavioral parameters, and dry eye-related indicators. These include critical flicker fusion frequency, visual fatigue questionnaire scores, eye movement, blinking and pupil parameters, tear film-related measurements, conjunctival redness, and dry eye symptom scores. Safety will be assessed by recording any discomfort or adverse events, such as glare discomfort, eye dryness, tearing, conjunctival redness, headache, nausea, or dizziness.
This study is expected to provide clinical evidence on whether full-spectrum screen bar lighting can help reduce screen-related visual fatigue and dry eye symptoms, and may support the development of lighting strategies for visual health in daily screen-use environments.
- Conditions
- Visual Fatigue, Dry Eye, Computer Vision Syndrome
- Being tested
- Full-spectrum screen bar light, Brightness-matched screen task without screen bar lighting
- Keywords
- Visual fatigue, Dry Eye, Computer vision syndrome, Critical flicker fusion frequency, Full-spectrum
- Medical subject headings
- Asthenopia, Dry Eye Syndromes
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Full-spectrum screen bar lightDevice
The full-spectrum screen bar light will be used as task lighting during an approximately 2-hour standardized screen task in a controlled laboratory environment. Participants will complete computer-based text processing, screen reading, or viewing of specified video materials to simulate prolonged near-screen use.
Brightness-matched screen task without screen bar lightingOther
Participants will complete the standardized screen task without using a screen bar light. Screen brightness will be adjusted to match the brightness condition of the full-spectrum screen bar lighting arm. The task type, content, duration, and completion requirements will be the same as those in the experimental arm.
| Study group | Role | What they receive |
|---|---|---|
| Full-Spectrum Screen Bar Lighting | Experimental | Participants assigned to this arm will complete an approximately 2-hour standardized screen task in a controlled laboratory environment using a full-spectrum screen bar light (MB23001032H-1B) as task lighting. The screen task may include computer-based text processing, screen reading, or viewing specified video materials. Task content, duration, and completion requirements will be kept consistent with the control arm. Receives: Device: Full-spectrum screen bar light |
| Brightness-Matched Control | Placebo comparator | Participants assigned to this arm will complete the same approximately 2-hour standardized screen task in the same controlled laboratory environment without using a full-spectrum screen bar light or any additional screen bar lighting. Screen brightness will be adjusted to match the brightness condition of the full-spectrum screen bar lighting arm. Task content, duration, and completion requirements will be kept consistent with the experimental arm. Receives: Other: Brightness-matched screen task without screen bar lighting |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in Critical Flicker Fusion Frequency
Critical flicker fusion frequency (CFF) will be measured in Hz using the Handy Flicker HF-III device. The outcome will be calculated as the post-task CFF value minus the baseline CFF value. This measure will be used as an objective indicator of visual fatigue after the standardized screen task.
Measured: Baseline and immediately after completion of the approximately 2-hour standardized screen task
Secondary outcomes (4)
Change in Computer Vision Syndrome Questionnaire Score
The Computer Vision Syndrome Questionnaire (CVS-Q) will be used to assess subjective visual fatigue symptoms. The outcome will be calculated as the post-task total score minus the baseline total score.
Measured: Baseline and immediately after completion of the approximately 2-hour standardized screen task
Change in EyeFatigue Tracker Ocular Behavioral Parameters
Ocular behavioral parameters will be recorded using the EyeFatigue Tracker system during a standardized 1-minute reading task. The assessment will include eye movement, blink, and pupil-related parameters. Change values will be calculated as post-task values minus baseline values.
Measured: Baseline and immediately after completion of the approximately 2-hour standardized screen task
Change in Keratograph 5M Ocular Surface Assessment
Objective ocular surface and dry eye-related parameters will be measured using the Keratograph 5M system. The assessment will include non-invasive tear breakup time, tear meniscus height, and conjunctival redness. Change values will be calculated as post-task values minus baseline values.
Measured: Baseline and immediately after completion of the approximately 2-hour standardized screen task
Change in Eye Dryness Score on the 0-100 Visual Analog Scale
Eye dryness will be assessed using the Eye Dryness Score on a 0-100 visual analog scale. Participants will indicate the severity of eye dryness by placing a mark on a 100-mm horizontal line, where 0 represents no eye dryness and 100 represents the most severe eye dryness. Higher scores indicate worse symptoms. The change score will be calculated as the score immediately after the standardized screen task minus the baseline score. A positive change indicates worsening of eye dryness, whereas a negative change indicates improvement.
Measured: Baseline and immediately after completion of the approximately 2-hour standardized screen task
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted15 Jul 2026
- Study start22 Sep 2026 (estimated)
- Primary completion1 Apr 2027 (estimated)
- Study completion1 Apr 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (4)Papers the sponsor has linked to this study.
- Other trials for Visual FatigueStudies 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
- Single blind
- Who is masked
- Outcomes assessor
- Enrolment
- 112 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Zhongshan Ophthalmic Center, Sun Yat-sen University
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07706231
- Sponsor's protocol ID
- SIT2026005
- Status last verified
- Sep 2026
- First submitted
- 9 Jul 2026
- Last updated
- 18 Sep 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
Chen H, Ratanapakorn T, Sukonpatip M, Asawaphureekorn S, Thinkhamrop W, Wang X, Eungpinichpong W. Effects of yoga facial massage on computer vision syndrome and ocular motor function: A randomised controlled trial. Complement Ther Med. 2025 Dec;95:103270. doi: 10.1016/j.ctim.2025.103270. Epub 2025 Oct 22.
PubMed 41135797Ide T, Toda I, Miki E, Tsubota K. Effect of Blue Light-Reducing Eye Glasses on Critical Flicker Frequency. Asia Pac J Ophthalmol (Phila). 2015 Mar-Apr;4(2):80-5. doi: 10.1097/APO.0000000000000069.
PubMed 26065349Singh S, Downie LE, Anderson AJ. Do Blue-blocking Lenses Reduce Eye Strain From Extended Screen Time? A Double-Masked Randomized Controlled Trial. Am J Ophthalmol. 2021 Jun;226:243-251. doi: 10.1016/j.ajo.2021.02.010. Epub 2021 Feb 12.
PubMed 33587901Lin JB, Gerratt BW, Bassi CJ, Apte RS. Short-Wavelength Light-Blocking Eyeglasses Attenuate Symptoms of Eye Fatigue. Invest Ophthalmol Vis Sci. 2017 Jan 1;58(1):442-447. doi: 10.1167/iovs.16-20663.
PubMed 28118668
Study at a glance
From the registry record, last updated by the sponsor on 18 Sep 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Randomized Controlled Trial of the Effects of Full-Spectrum Screen Bar Lighting on Visual Fatigue and Dry Eye After a Standardized Screen Task
- ClinicalTrials.gov ID
- NCT07706231
- Acronym / sponsor ID
- SIT2026005
- Conditions
- Visual Fatigue, Dry Eye, Computer Vision Syndrome
- Keywords
- Visual fatigue, Dry Eye, Computer vision syndrome, Critical flicker fusion frequency, Full-spectrum
- Study type
- Interventional
- Recruitment status
- Not yet recruiting
- Enrolment
- 112 participants (estimated)
- Lead sponsor
- Zhongshan Ophthalmic Center, Sun Yat-sen UniversityUniversity, hospital or other
- Study start
- 22 Sep 2026 (estimated)
- Primary completion
- 1 Apr 2027 (estimated)
- Study completion
- 1 Apr 2027 (estimated)
- First posted
- 15 Jul 2026 (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 will evaluate whether full-spectrum screen bar lighting can reduce eye fatigue and dry eye symptoms after a standardized screen task. Prolonged screen use is common in daily work and study and may cause blurred vision, eye soreness, dryness, headache, and reduced attention. Light environment may be one way to improve visual comfort during screen use, but more controlled clinical evidence is needed.
In this randomized, parallel-group controlled study, 112 healthy adult participants will be assigned to either a full-spectrum screen bar lighting group or a brightness-matched control group without screen bar lighting. Participants in both groups will complete an approximately 2-hour standardized screen task in a controlled laboratory environment. The study will compare changes before and after the task in objective and subjective measures of visual fatigue and dry eye, including critical flicker fusion frequency, visual fatigue questionnaire scores, eye movement and blinking parameters, pupil parameters, tear film-related measurements, and dry eye symptom scores. Safety and discomfort during the study will also be recorded.
Detailed description
Prolonged use of electronic screens is increasingly common in work, study, and daily life and may lead to visual fatigue and dry eye-related symptoms. These symptoms may include blurred vision, eye soreness, dryness, headache, and reduced attention. Although behavioral strategies such as taking breaks and adjusting viewing distance are commonly recommended, their effectiveness may be limited by individual adherence. Optimizing the lighting environment during screen use may provide a standardized and practical approach to improving visual comfort.
This is a single-center, randomized, parallel-group controlled study designed to evaluate the effects of full-spectrum screen bar lighting during a standardized screen task. Eligible healthy adult participants with regular daily screen exposure will be randomly assigned in a 1:1 ratio to either a full-spectrum screen bar lighting group or a brightness-matched control group without screen bar lighting. Both groups will complete the same approximately 2-hour standardized screen task in a controlled laboratory environment. The task may include computer-based text processing, screen reading, or viewing specified video materials, with the task content, duration, and completion requirements kept consistent between groups.
Assessments will be performed before and immediately after the standardized screen task. The study will evaluate changes in objective and subjective measures of visual fatigue, ocular behavioral parameters, and dry eye-related indicators. These include critical flicker fusion frequency, visual fatigue questionnaire scores, eye movement, blinking and pupil parameters, tear film-related measurements, conjunctival redness, and dry eye symptom scores. Safety will be assessed by recording any discomfort or adverse events, such as glare discomfort, eye dryness, tearing, conjunctival redness, headache, nausea, or dizziness.
This study is expected to provide clinical evidence on whether full-spectrum screen bar lighting can help reduce screen-related visual fatigue and dry eye symptoms, and may support the development of lighting strategies for visual health in daily screen-use environments.
Study design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind (outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Full-Spectrum Screen Bar Lighting | Experimental | Device: Full-spectrum screen bar lightParticipants assigned to this arm will complete an approximately 2-hour standardized screen task in a controlled laboratory environment using a full-spectrum screen bar light (MB23001032H-1B) as task lighting. The screen task may include computer-based text processing, screen reading, or viewing specified video materials. Task content, duration, and completion requirements will be kept consistent with the control arm. |
| Brightness-Matched Control | Placebo comparator | Other: Brightness-matched screen task without screen bar lightingParticipants assigned to this arm will complete the same approximately 2-hour standardized screen task in the same controlled laboratory environment without using a full-spectrum screen bar light or any additional screen bar lighting. Screen brightness will be adjusted to match the brightness condition of the full-spectrum screen bar lighting arm. Task content, duration, and completion requirements will be kept consistent with the experimental arm. |
Who may qualify
- Ages
- 18 to 35 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (4 listed)
- Age 18 to 35 years, male or female.
- Average daily electronic screen exposure of at least 4 hours.
- Near visual acuity at 40 cm of 0.5 or better, and able to complete the study 1. tasks and measurements stably.
- Able and willing to provide written informed consent.
Key exclusion criteria (12 listed)
- Presence of ocular inflammation or ocular disease.
- History of severe systemic disease, neurological disease, or psychiatric disorder.
- Use of dry eye or visual fatigue treatments, or contact lens wear, within 1 month before the study.
- History of ocular surgery within the past 6 months.
- Daily use of lenses with blue-light blocking, photochromic, polarized, filtering, or similar optical functions.
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 |
|---|---|---|
| Full-spectrum screen bar lightThe full-spectrum screen bar light will be used as task lighting during an approximately 2-hour standardized screen task in a controlled laboratory environment. Participants will complete computer-based text processing, screen reading, or viewing of specified video materials to simulate prolonged near-screen use. | Device | Full-Spectrum Screen Bar Lighting |
| Brightness-matched screen task without screen bar lightingParticipants will complete the standardized screen task without using a screen bar light. Screen brightness will be adjusted to match the brightness condition of the full-spectrum screen bar lighting arm. The task type, content, duration, and completion requirements will be the same as those in the experimental arm. | Other | Brightness-Matched Control |
Primary outcome
Change in Critical Flicker Fusion Frequency
Time frame: Baseline and immediately after completion of the approximately 2-hour standardized screen task
Critical flicker fusion frequency (CFF) will be measured in Hz using the Handy Flicker HF-III device. The outcome will be calculated as the post-task CFF value minus the baseline CFF value. This measure will be used as an objective indicator of visual fatigue after the standardized screen task.
4 secondary outcomes
Change in Computer Vision Syndrome Questionnaire Score
Time frame: Baseline and immediately after completion of the approximately 2-hour standardized screen task
Change in EyeFatigue Tracker Ocular Behavioral Parameters
Time frame: Baseline and immediately after completion of the approximately 2-hour standardized screen task
Change in Keratograph 5M Ocular Surface Assessment
Time frame: Baseline and immediately after completion of the approximately 2-hour standardized screen task
Change in Eye Dryness Score on the 0-100 Visual Analog Scale
Time frame: Baseline and immediately after completion of the approximately 2-hour standardized screen task
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 18 Sep 2026.
- Background: PubMed 41135797Chen H, Ratanapakorn T, Sukonpatip M, Asawaphureekorn S, Thinkhamrop W, Wang X, Eungpinichpong W. Effects of yoga facial massage on computer vision syndrome and ocular motor function: A randomised controlled trial. Complement Ther Med. 2025 Dec;95:103270. doi: 10.1016/j.ctim.2025.103270. Epub 2025 Oct 22.
- Background: PubMed 26065349Ide T, Toda I, Miki E, Tsubota K. Effect of Blue Light-Reducing Eye Glasses on Critical Flicker Frequency. Asia Pac J Ophthalmol (Phila). 2015 Mar-Apr;4(2):80-5. doi: 10.1097/APO.0000000000000069.
- Background: PubMed 33587901Singh S, Downie LE, Anderson AJ. Do Blue-blocking Lenses Reduce Eye Strain From Extended Screen Time? A Double-Masked Randomized Controlled Trial. Am J Ophthalmol. 2021 Jun;226:243-251. doi: 10.1016/j.ajo.2021.02.010. Epub 2021 Feb 12.
- Background: PubMed 28118668Lin JB, Gerratt BW, Bassi CJ, Apte RS. Short-Wavelength Light-Blocking Eyeglasses Attenuate Symptoms of Eye Fatigue. Invest Ophthalmol Vis Sci. 2017 Jan 1;58(1):442-447. doi: 10.1167/iovs.16-20663.
- Individual participant dataSharing planned: No
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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.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Full-spectrum screen bar light and Brightness-matched screen task without screen bar lighting in people with Visual Fatigue and Dry Eye, run by Zhongshan Ophthalmic Center, Sun Yat-sen 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 12 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: opening soon, as of the sponsor's last update on 18 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?
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?
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?
Change in Critical Flicker Fusion Frequency (time frame: Baseline and immediately after completion of the approximately 2-hour standardized screen task). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT07706231, which also lists 4 linked publications.
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 18 Sep 2026.