Digital Eye StrainNCT07340359
Effect of Yellow Light AG Mobile Phone Screen on Dry Eye and Asthenopia.
A study testing reading 2h on smartphone in people with Digital Eye Strain and Computer Vision Syndrome, run by Second Affiliated Hospital, Zhejiang University, School of Medicine at 1 site in China.
Trial summary
This study aimed to evaluate the protective effects of yellow-light etching anti-glare (AG) screen on Digital Eye Strain (DES) induced by prolonged video display terminal (VDT) use under dim environment, Based on the proved positive effect of the circular polarization (CP) screen, providing insights for new… Read more about this study
- Who is it for?
- Ages 18 to 40 yearsHealthy volunteers can take part
- Conditions the study is for
- Digital Eye Strain, Computer Vision Syndrome, Dry Eye
- What is being tested?
- reading 2h on smartphone
- Type of treatment
- Lifestyle or therapy programme
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 70 participants
- Where
- 1 siteChina
- Study dates
- 10 Jan 2026to 21 Feb 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 40 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- 1.have basic reading comprehension skills and to be older than 18 years old. 2.diopter of both eyes not exceeding -6.0D and anisometropia not exceeding 2.0D.
Who cannot join
- 1.presbyopia or decreased regulation function, 2.ocular inflammation and disease, 3.worn contact lens within 1 month, 4.history of eye surgery within 6 months, 5.lactating or pregnant woman, 6.have severe systemic diseases.
Trial locations and contacts
1 site in 1 country.
China1 site
The Second Affiliated Hospital Zhejiang University School of Medicine (SAHZU)
Hangzhou, Zhejiang, 310000
About this study
This study aimed to evaluate the protective effects of yellow-light etching anti-glare (AG) screen on Digital Eye Strain (DES) induced by prolonged video display terminal (VDT) use under dim environment, Based on the proved positive effect of the circular polarization (CP) screen, providing insights for new eye-protection strategy in the highly digital modern era. In a randomized, double-blind controlled trial, 70 eligible volunteers (diopter ≤ -6.0D; anisometropia ≤ 2.0D) were divided into AG+CP or CP only groups. Participants performed a 2-hour e-book reading task using assigned AG+CP or CP only smartphones. Subjects' severity of DES pre- and post-reading were evaluated from two aspects: the degree of dry eye symptoms and asthenopia. Dry eye symptoms indicators (OSDI, TMH, NIBUT, FBUT, CFS, Schirmer I Test) and asthenopia indicators (CVSS17, Bulbar redness, HFC) were measured and compared.
Read the detailed description
The inclusion criteria required subjects to have myopia diopter not exceeding -6.00D, hyperopia not exceeding +2.0D, astigmatism not exceeding -2.00D, anisometropia between both eyes not exceeding 2.00D. The key exclusion criteria were as follows: (1) strabismus and amblyopia; (2) used eye drops within 1 week; (3) had undergone eye surgery within 6 months; (4) worn contact lenses within the last 2 weeks; (5) had serious eye discomfort in the last 7 days; (6) breastfeeding or pregnant women and patients with severe systemic diseases, psychosis or dementia. Subjects did not know the characteristics of the smartphones they use. The subjects were asked not to use video terminals such as mobile phones within 30 minutes before the study began.
Subjects were divided into 2 groups using AG+CP or CP only smartphone provided. During the whole experiment, subjects were in a room with 2 lux-environment illuminance, screen brightness about 10nit to mimic the situation before sleep. Light source stability (working surface illuminance fluctuation) greater than 99% during the whole experiment, desktop range uniformity greater than 80%. Indoor air conditioning control temperature: 22-25 degrees Celsius, humidity: 50-70%RH. Mobile phones were placed on a fixed holder (the angle and height of the phone holder can be adjusted to ensure the suitability of participants). All subjects' eyes were 40cm away from the mobile phone screen and seated on a chair of fixed position and appropriate height. Subjects were asked to finish 2-hour reading on the specific smartphone. Reading materials are downloaded in advance to the smartphone and presented using specific reading software and settings. During the study period, subjects were not allowed to do any behavior unrelated to watching the screen for a long time (more than 1 minute). All experiments were conducted between 8:00 and 11:00 to minimize the impact of electronic screen use during the day. Ocular surface disease index (OSDI), tear meniscus height (TMH), noninvasive tear break-up time (NIBUT), Fluorescein tear break-up time (FBUT), corneal fluorescein staining (CFS) and Schirmer I test were measured to evaluate the degree of dry eye symptom. Computer vision syndrome scale 17 (CVSS17), bulbar redness and high-frequency component of accommodative microfluctuations (HFC), were identified as assessment of asthenopia. The intervention and assessments were delivered both at before and after smartphone reading by qualified clinical ophthalmologists in a hospital setting.
- Conditions
- Digital Eye Strain, Computer Vision Syndrome, Dry Eye, Asthenopia
- Being tested
- reading 2h on smartphone
- Medical subject headings
- Dry Eye Syndromes, Asthenopia
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
reading 2h on smartphoneBehavioural
reading 2h on smartphone
| Study group | Role | What they receive |
|---|---|---|
| yellow light AG group | Experimental | use yellow light AG smartphone Receives: Behavioral: reading 2h on smartphone |
| control group | Placebo comparator | use non-yellow light AG smartphone Receives: Behavioral: reading 2h on smartphone |
What is being measured
The primary outcome is the main question the study is designed to answer.
Flourescence tear break-up time
Drop a drop of physiological saline onto a sodium fluorescein test strip. Gently touch the middle of the conjunctiva of both lower eyelids of the examinee with the test strip respectively, and instruct the examinee to blink their eyes gently and look straight ahead. The examiner observed the tear film of the examinee with cobalt blue light under a slit lamp. The time of tear film rupture was the time from the examinee opening their eyes to the appearance of the first black spot on the tear film. Three TBUT tests were detected and recorded for each eye respectively, and the average and maximum values were taken.
Measured: 1 month
HFC (high frequency component of accommodative fluctuation)
The SCR mode of the ACOMOREF K-MODEL computerized optometer was adopted. The subjects were asked to keep a close eye on the image. The image distance was gradually moved from infinity to 1m, 60cm, and 30cm, and remained at each of the four distances for 20 seconds. The equipment would analyze and record the high-frequency fluctuations of the subjects' ciliary muscles, known as HFC. After the test of the first eye, Take a 20-second break to test the second eye.
Measured: 1 month
non-invasive tear break-up time
The Oculus ocular surface comprehensive analyzer was adopted. The examinees sat upright in front of the instrument and were asked to blink their eyes lightly and then look at the red marked object. The instrument automatically conducted ocular surface image analysis to obtain and record the first NIBUT and average NIBUT of the examinees
Measured: 1 month
Secondary outcomes (4)
tear meniscus height
The Oculus ocular surface comprehensive analyzer was used. The person being examined sat upright in front of the instrument and was asked to blink their eyes slightly and then look at the red marked object. The instrument automatically analyzed the ocular surface images to obtain the lacrimal river height data
Measured: 1 month
corneal fluorescein staining
After character searching, gaming and video tasks utilizing specific smartphones for totally 45 minutes, CFS was measured.
Measured: 1 month
computer vision symptom scale 17
A subjective scale reflecting the symptoms of visual fatigue, including the occurrence frequency and intensity of 17 ocular and extraocular symptoms
Measured: 1 month
Schirmer I test
The subjects were tested under non-anesthetic conditions. A 5mm×35mm filter paper was placed in the conjunctival sac of the inner 1/3 of the lower eyelid, with the remaining part hanging over the skin surface. The subjects were asked to gently close their eyes. After 5 minutes, the length of the filter paper soaked by tears was measured and recorded
Measured: 1 month
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted14 Jan 2026
- Study start10 Jan 2026
- Primary completion21 Jan 2026
- Study completion21 Feb 2026
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Digital Eye StrainStudies of the same condition, open and under way.
- More trials run by Second Affiliated Hospital, Zhejiang University, School of MedicineThe 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
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind
- Who is masked
- Participant, Investigator
- Enrolment
- 70 participants (actual)
Sponsor and investigators
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07340359
- Sponsor's protocol ID
- 2025-1513
- Status last verified
- Dec 2025
- First submitted
- 6 Jan 2026
- Last updated
- 5 Mar 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 5 Mar 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Effect of Yellow Light AG Mobile Phone Screen on Dry Eye and Asthenopia.
- ClinicalTrials.gov ID
- NCT07340359
- Acronym / sponsor ID
- 2025-1513
- Conditions
- Digital Eye Strain, Computer Vision Syndrome, Dry Eye, Asthenopia
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 70 participants (actual)
- Lead sponsor
- Second Affiliated Hospital, Zhejiang University, School of MedicineUniversity, hospital or other
- Study start
- 10 Jan 2026 (actual)
- Primary completion
- 21 Jan 2026 (actual)
- Study completion
- 21 Feb 2026 (actual)
- First posted
- 14 Jan 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 aimed to evaluate the protective effects of yellow-light etching anti-glare (AG) screen on Digital Eye Strain (DES) induced by prolonged video display terminal (VDT) use under dim environment, Based on the proved positive effect of the circular polarization (CP) screen, providing insights for new eye-protection strategy in the highly digital modern era. In a randomized, double-blind controlled trial, 70 eligible volunteers (diopter ≤ -6.0D; anisometropia ≤ 2.0D) were divided into AG+CP or CP only groups. Participants performed a 2-hour e-book reading task using assigned AG+CP or CP only smartphones. Subjects' severity of DES pre- and post-reading were evaluated from two aspects: the degree of dry eye symptoms and asthenopia. Dry eye symptoms indicators (OSDI, TMH, NIBUT, FBUT, CFS, Schirmer I Test) and asthenopia indicators (CVSS17, Bulbar redness, HFC) were measured and compared.
Detailed description
The inclusion criteria required subjects to have myopia diopter not exceeding -6.00D, hyperopia not exceeding +2.0D, astigmatism not exceeding -2.00D, anisometropia between both eyes not exceeding 2.00D. The key exclusion criteria were as follows: (1) strabismus and amblyopia; (2) used eye drops within 1 week; (3) had undergone eye surgery within 6 months; (4) worn contact lenses within the last 2 weeks; (5) had serious eye discomfort in the last 7 days; (6) breastfeeding or pregnant women and patients with severe systemic diseases, psychosis or dementia. Subjects did not know the characteristics of the smartphones they use. The subjects were asked not to use video terminals such as mobile phones within 30 minutes before the study began.
Subjects were divided into 2 groups using AG+CP or CP only smartphone provided. During the whole experiment, subjects were in a room with 2 lux-environment illuminance, screen brightness about 10nit to mimic the situation before sleep. Light source stability (working surface illuminance fluctuation) greater than 99% during the whole experiment, desktop range uniformity greater than 80%. Indoor air conditioning control temperature: 22-25 degrees Celsius, humidity: 50-70%RH. Mobile phones were placed on a fixed holder (the angle and height of the phone holder can be adjusted to ensure the suitability of participants). All subjects' eyes were 40cm away from the mobile phone screen and seated on a chair of fixed position and appropriate height. Subjects were asked to finish 2-hour reading on the specific smartphone. Reading materials are downloaded in advance to the smartphone and presented using specific reading software and settings. During the study period, subjects were not allowed to do any behavior unrelated to watching the screen for a long time (more than 1 minute). All experiments were conducted between 8:00 and 11:00 to minimize the impact of electronic screen use during the day. Ocular surface disease index (OSDI), tear meniscus height (TMH), noninvasive tear break-up time (NIBUT), Fluorescein tear break-up time (FBUT), corneal fluorescein staining (CFS) and Schirmer I test were measured to evaluate the degree of dry eye symptom. Computer vision syndrome scale 17 (CVSS17), bulbar redness and high-frequency component of accommodative microfluctuations (HFC), were identified as assessment of asthenopia. The intervention and assessments were delivered both at before and after smartphone reading by qualified clinical ophthalmologists in a hospital setting.
Study design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind (participant, investigator)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| yellow light AG group | Experimental | Behavioral: reading 2h on smartphoneuse yellow light AG smartphone |
| control group | Placebo comparator | Behavioral: reading 2h on smartphoneuse non-yellow light AG smartphone |
Who may qualify
- Ages
- 18 to 40 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (1 listed)
- 1.have basic reading comprehension skills and to be older than 18 years old. 2.diopter of both eyes not exceeding -6.0D and anisometropia not exceeding 2.0D.
Key exclusion criteria (1 listed)
- 1.presbyopia or decreased regulation function, 2.ocular inflammation and disease, 3.worn contact lens within 1 month, 4.history of eye surgery within 6 months, 5.lactating or pregnant woman, 6.have severe systemic diseases.
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 |
|---|---|---|
| reading 2h on smartphonereading 2h on smartphone | Behavioural | control group, yellow light AG group |
Primary outcome
Flourescence tear break-up time
Time frame: 1 month
Drop a drop of physiological saline onto a sodium fluorescein test strip. Gently touch the middle of the conjunctiva of both lower eyelids of the examinee with the test strip respectively, and instruct the examinee to blink their eyes gently and look straight ahead. The examiner observed the tear film of the examinee with cobalt blue light under a slit lamp. The time of tear film rupture was the time from the examinee opening their eyes to the appearance of the first black spot on the tear film. Three TBUT tests were detected and recorded for each eye respectively, and the average and maximum values were taken.
HFC (high frequency component of accommodative fluctuation)
Time frame: 1 month
The SCR mode of the ACOMOREF K-MODEL computerized optometer was adopted. The subjects were asked to keep a close eye on the image. The image distance was gradually moved from infinity to 1m, 60cm, and 30cm, and remained at each of the four distances for 20 seconds. The equipment would analyze and record the high-frequency fluctuations of the subjects' ciliary muscles, known as HFC. After the test of the first eye, Take a 20-second break to test the second eye.
non-invasive tear break-up time
Time frame: 1 month
The Oculus ocular surface comprehensive analyzer was adopted. The examinees sat upright in front of the instrument and were asked to blink their eyes lightly and then look at the red marked object. The instrument automatically conducted ocular surface image analysis to obtain and record the first NIBUT and average NIBUT of the examinees
4 secondary outcomes
tear meniscus height
Time frame: 1 month
corneal fluorescein staining
Time frame: 1 month
computer vision symptom scale 17
Time frame: 1 month
Schirmer I test
Time frame: 1 month
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 5 Mar 2026.
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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. This study is not recruiting at the moment.
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 reading 2h on smartphone in people with Digital Eye Strain and Computer Vision Syndrome, run by Second Affiliated Hospital, Zhejiang University, School of Medicine 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 1 inclusion and 1 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 5 Mar 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?
Flourescence tear break-up time (time frame: 1 month). 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 5 Mar 2026.