AsthenopiaNCT06745661
Impact of Red Light Therapy on Alleviating Visual Fatigue in Presbyopes
A study testing RLRL device in people with Asthenopia and Visual Fatigue, run by The Hong Kong Polytechnic University at 1 site in Hong Kong.
Trial summary
Visual fatigue, or asthenopia, occurs when visual demands exceed the capacity of the visual system, leading to various ocular discomfort and systemic symptoms. This condition can negatively affect personal activities, quality of life, and work productivity. Read more about this study
- Who is it for?
- Ages 40 years and older
- Conditions the study is for
- Asthenopia, Visual Fatigue, Presbyopia
- What is being tested?
- RLRL device
- Type of treatment
- Medical device
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 66 participants
- Where
- 1 siteHong Kong
- Study dates
- 10 Feb 2025to 23 May 2025
- 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 40 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Individuals aged over 40 years old.
- Self-reported visual fatigue symptoms.
- Distance best-corrected visual acuity (BCVA) of 0.5 LogMAR or better, and near visual acuity worse than N8 (20/50) at 40 cm with the subject's habitual distance correction.
- Require near correction in daily life.
- No light therapy received in the past six months.
- Giving informed written consent.
Who cannot join
- Presence of diseases that can cause eye pain or headaches, such as strabismus, glaucoma, ocular trauma, conjunctivitis, migraines, keratitis, iridocyclitis, or other self-reported diseases.
- Systemic diseases (e.g., epilepsy, photosensitivity, seizure) or illiteracy.
- Afterimage time longer than 6 minutes.
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Investigating the Impact of RLRL on Alleviating Visual Fatigue in Presbyopic Population
Visual fatigue, or asthenopia, occurs when visual demands exceed the capacity of the visual system, leading to various ocular discomfort and systemic symptoms. This condition can negatively affect personal activities, quality of life, and work productivity. Given the high prevalence of asthenopia in presbyopic population, finding effective methods to alleviate these symptoms is crucial. This study aims to evaluate the effects of repeated low-level red-light (RLRL) therapy on alleviating visual fatigue in individuals with presbyopia over a one-month period. Additionally, we will assess the potential benefits on accommodation function, cognition, and emotional effects of RLRL in this population.
Interested individuals will be invited to the PolyU Optometry Clinic to undergo an eligibility examination. An estimated sample size of 66 participants will be recruited. The inclusion criteria specify individuals aged 40 years or older who self-report visual fatigue symptoms and require near correction in daily life. Exclusion criteria include those with ocular disease, systemic diseases, illiteracy, or an afterimage duration longer than 6 minutes.
Read more
Eligible participants will be randomly assigned in a 1:1 ratio to either the intervention group or the control group. Each participant in the intervention group will be provided an RLRL therapy device, which they are required to use twice daily for 3 minutes per session, with a minimum interval of 4 hours between sessions, 7 days a week for one month. Participants in the control group will receive a sham device, following the same usage schedule. The study will evaluate changes in asthenopia questionnaire scores, CFF scores, other objective asthenopia indicators (i.e., eye movement, pupil parameters, and blink patterns), accommodation function, cognitive function, and emotional states at 2 weeks and 1 month compared to baseline. Statistical analysis will be conducted to explore evaluate within-subject changes over time and between-group differences in visual fatigue metrics, accommodation metrics, cognitive metrics, and emotional metrics.
The findings will contribute to evaluating the effectiveness of RLRL therapy in reducing asthenopia and presbyopia symptoms, as well as its impact on cognitive function and emotional well-being.
- Conditions
- Asthenopia, Visual Fatigue, Presbyopia
- Being tested
- RLRL device, sham device
- Keywords
- asthenopia, visual fatigue, presbyopia, red light therapy
- Medical subject headings
- Asthenopia, Presbyopia
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
RLRL deviceDevice
Each participant in the intervention group will be provided a repeated low-level red-light therapy (RLRL) device, which they are required to use twice daily for 3 minutes per session, with a minimum interval of 4 hours between sessions, 7 days a week for one month.
sham deviceDevice
Each participant in the sham group will be provided a sham therapy device, which they are required to use twice daily for 3 minutes per session, with a minimum interval of 4 hours between sessions, 7 days a week for one month.
| Study group | Role | What they receive |
|---|---|---|
| RLRL therapy group | Experimental | The experimental group will undergo repeated low-level red-light therapy (RLRL). The light power through a 4-mm pupil is 0.29 mW for the RLRL device. Receives: Device: RLRL device |
| Sham therapy group | Sham comparator | The sham group will use a sham device, which operates at only 10% of the active RLRL device's power. The light power through a 4-mm pupil is 0.03 mW for the sham device. Receives: Device: sham device |
What is being measured
The primary outcome is the main question the study is designed to answer.
change in the asthenopia questionnaire scores
The primary outcome is the change in the asthenopia questionnaire scores at 2 weeks and 1 month compared to baseline. These scores will be derived from the Computer Vision Syndrome Questionnaire (CVS-Q), a widely recognized tool for assessing subjective symptoms of asthenopia. The CVS-Q ranges from 0 (no symptoms) to 32 (most severe), with higher scores indicating worse symptoms (negative change = improvement)
Measured: at 2 weeks and 1 month compared to baseline
Secondary outcomes (9)
Change in critical flicker fusion frequency (CFF)
•Change in CFF at 2 weeks and 1 month compared to baseline.
Measured: at 2 weeks and 1 month compared to baseline
Change in eye movement
•Change in eye movement at 2 weeks and 1 month compared to baseline.
Measured: at 2 weeks and 1 month compared to baseline
Change in pupil parameters
•Change in pupil parameters at 2 weeks and 1 month compared to baseline.
Measured: at 2 weeks and 1 month compared to baseline
Change in blink patterns
•Change in blink patterns at 2 weeks and 1 month compared to baseline.
Measured: at 2 weeks and 1 month compared to baseline
Change in accommodation function
•Change in accommodation function at 2 weeks and 1 month compared to baseline.
Measured: at 2 weeks and 1 month compared to baseline
Change in self-reported emotional states
Change in self-reported emotional states, assessed by the Positive and Negative Affect Schedule (PANAS-X) at 2 weeks and 1 month compared to baseline. The scores are divided into positive scores and negative scores. Items are rated for the past week on a 5-point scale. The Positive Affect subscale (items 1,3,5,9,10,12,14,16,17,19) and Negative Affect subscale (items 2,4,6,7,8,11,13,15,18,20) each total 10-50 points.
Positive Affect Score: Higher scores indicate higher levels of positive affect. Negative Affect Score: Lower scores indicate lower levels of negative affect.
Measured: at 2 weeks and 1 month compared to baseline
Change in electroencephalogram (EEG)
•Change EEG at 2 weeks and 1 month compared to baseline.
Measured: at 2 weeks and 1 month compared to baseline
Change in cognitive questionnaire
•Change in cognitive questionnaire, measured by the Montreal Cognitive Assessment Scale (MoCA) at 2 weeks and 1 month compared to baseline. Total score 0-30; higher scores indicate better cognitive function.
Measured: at 2 weeks and 1 month compared to baseline
Change in near activity visual questionnaire
Change in near activity visual questionnaire (NAVQ) score at 2 weeks and 1 month compared to baseline. Scores are reported on the Rasch-transformed 0-100 scale, with higher scores indicating worse near-vision function (decreases = improvement).
Measured: at 2 weeks and 1 month compared to baseline
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted20 Dec 2024
- Study start10 Feb 2025
- Primary completion23 May 2025
- Study completion23 May 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for AsthenopiaStudies of the same condition, open and under way.
- More trials run by The Hong Kong Polytechnic UniversityThe 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
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 66 participants (actual)
Sponsor and investigators
- Lead sponsor
- The Hong Kong Polytechnic University
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06745661
- Sponsor's protocol ID
- HSEARS20240916007
- Status last verified
- Dec 2024
- First submitted
- 8 Dec 2024
- Last updated
- 24 Sep 2025
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: According to the relevant agreement, all parties involved must keep study data confidential throughout the study process.
Publications
Song F, Zhao Z, Zhang J, Li J, Wu Y, Liu Y, Li P, Wang Y, Lai M, He M, Chen Y. Repeated low-level red-light therapy for improving asthenopic symptoms and accommodation in presbyopia. Ann Med. 2026 Dec;58(1):2663105. doi: 10.1080/07853890.2026.2663105. Epub 2026 Apr 28.
PubMed 42046494
Study at a glance
From the registry record, last updated by the sponsor on 24 Sep 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Investigating the Impact of RLRL on Alleviating Visual Fatigue in Presbyopic Population
- ClinicalTrials.gov ID
- NCT06745661
- Acronym / sponsor ID
- HSEARS20240916007
- Conditions
- Asthenopia, Visual Fatigue, Presbyopia
- Keywords
- asthenopia, visual fatigue, presbyopia, red light therapy
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 66 participants (actual)
- Lead sponsor
- The Hong Kong Polytechnic UniversityUniversity, hospital or other
- Study start
- 10 Feb 2025 (actual)
- Primary completion
- 23 May 2025 (actual)
- Study completion
- 23 May 2025 (actual)
- First posted
- 20 Dec 2024 (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.
Visual fatigue, or asthenopia, occurs when visual demands exceed the capacity of the visual system, leading to various ocular discomfort and systemic symptoms. This condition can negatively affect personal activities, quality of life, and work productivity. Given the high prevalence of asthenopia in presbyopic population, finding effective methods to alleviate these symptoms is crucial. This study aims to evaluate the effects of repeated low-level red-light (RLRL) therapy on alleviating visual fatigue in individuals with presbyopia over a one-month period. Additionally, we will assess the potential benefits on accommodation function, cognition, and emotional effects of RLRL in this population.
Interested individuals will be invited to the PolyU Optometry Clinic to undergo an eligibility examination. An estimated sample size of 66 participants will be recruited. The inclusion criteria specify individuals aged 40 years or older who self-report visual fatigue symptoms and require near correction in daily life. Exclusion criteria include those with ocular disease, systemic diseases, illiteracy, or an afterimage duration longer than 6 minutes.
Eligible participants will be randomly assigned in a 1:1 ratio to either the intervention group or the control group. Each participant in the intervention group will be provided an RLRL therapy device, which they are required to use twice daily for 3 minutes per session, with a minimum interval of 4 hours between sessions, 7 days a week for one month. Participants in the control group will receive a sham device, following the same usage schedule. The study will evaluate changes in asthenopia questionnaire scores, CFF scores, other objective asthenopia indicators (i.e., eye movement, pupil parameters, and blink patterns), accommodation function, cognitive function, and emotional states at 2 weeks and 1 month compared to baseline. Statistical analysis will be conducted to explore evaluate within-subject changes over time and between-group differences in visual fatigue metrics, accommodation metrics, cognitive metrics, and emotional metrics.
The findings will contribute to evaluating the effectiveness of RLRL therapy in reducing asthenopia and presbyopia symptoms, as well as its impact on cognitive function and emotional well-being.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind (participant, care provider, investigator, outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| RLRL therapy group | Experimental | Device: RLRL deviceThe experimental group will undergo repeated low-level red-light therapy (RLRL). The light power through a 4-mm pupil is 0.29 mW for the RLRL device. |
| Sham therapy group | Sham comparator | Device: sham deviceThe sham group will use a sham device, which operates at only 10% of the active RLRL device's power. The light power through a 4-mm pupil is 0.03 mW for the sham device. |
Who may qualify
- Ages
- 40 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (6 listed)
- Individuals aged over 40 years old.
- Self-reported visual fatigue symptoms.
- Distance best-corrected visual acuity (BCVA) of 0.5 LogMAR or better, and near visual acuity worse than N8 (20/50) at 40 cm with the subject's habitual distance correction.
- Require near correction in daily life.
- No light therapy received in the past six months.
Key exclusion criteria (3 listed)
- Presence of diseases that can cause eye pain or headaches, such as strabismus, glaucoma, ocular trauma, conjunctivitis, migraines, keratitis, iridocyclitis, or other self-reported diseases.
- Systemic diseases (e.g., epilepsy, photosensitivity, seizure) or illiteracy.
- Afterimage time longer than 6 minutes.
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 |
|---|---|---|
| RLRL deviceEach participant in the intervention group will be provided a repeated low-level red-light therapy (RLRL) device, which they are required to use twice daily for 3 minutes per session, with a minimum interval of 4 hours between sessions, 7 days a week for one month. | Device | RLRL therapy group |
| sham deviceEach participant in the sham group will be provided a sham therapy device, which they are required to use twice daily for 3 minutes per session, with a minimum interval of 4 hours between sessions, 7 days a week for one month. | Device | Sham therapy group |
Primary outcome
change in the asthenopia questionnaire scores
Time frame: at 2 weeks and 1 month compared to baseline
The primary outcome is the change in the asthenopia questionnaire scores at 2 weeks and 1 month compared to baseline. These scores will be derived from the Computer Vision Syndrome Questionnaire (CVS-Q), a widely recognized tool for assessing subjective symptoms of asthenopia. The CVS-Q ranges from 0 (no symptoms) to 32 (most severe), with higher scores indicating worse symptoms (negative change = improvement)
9 secondary outcomes
Change in critical flicker fusion frequency (CFF)
Time frame: at 2 weeks and 1 month compared to baseline
Change in eye movement
Time frame: at 2 weeks and 1 month compared to baseline
Change in pupil parameters
Time frame: at 2 weeks and 1 month compared to baseline
Change in blink patterns
Time frame: at 2 weeks and 1 month compared to baseline
Change in accommodation function
Time frame: at 2 weeks and 1 month compared to baseline
Change in self-reported emotional states
Time frame: at 2 weeks and 1 month compared to baseline
Change in electroencephalogram (EEG)
Time frame: at 2 weeks and 1 month compared to baseline
Change in cognitive questionnaire
Time frame: at 2 weeks and 1 month compared to baseline
Change in near activity visual questionnaire
Time frame: at 2 weeks and 1 month compared to baseline
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 24 Sep 2025.
- Derived from this study: PubMed 42046494Song F, Zhao Z, Zhang J, Li J, Wu Y, Liu Y, Li P, Wang Y, Lai M, He M, Chen Y. Repeated low-level red-light therapy for improving asthenopic symptoms and accommodation in presbyopia. Ann Med. 2026 Dec;58(1):2663105. doi: 10.1080/07853890.2026.2663105. Epub 2026 Apr 28.
- Individual participant dataSharing planned: No. According to the relevant agreement, all parties involved must keep study data confidential throughout the study process.
Related trials for Asthenopia
Recruiting
Lactic Acid Bacteria for Reducing Blue Light-Induced Eye Fatigue
Digital Eye Strain (DES)
Not yet recruiting
Comparative Effects of Exercises on Pain, Cervical Proprioception, Neck Disability and Visual Performance in Patients With Computer Vision Syndrome.
Computer Vision Syndrome
Not yet recruiting
Study of Eye Fatigue From Digital Screens and Its Impact on Visual Performance in People With Normal Vision and Myopia, With and Without Dry Eye Symptoms and Signs
Myopia, Dry Eye Disease (DED)
Not yet recruiting
A Study of Full-Spectrum Screen Lighting for Reducing Screen-Related Eye Fatigue and Dry Eye
Visual Fatigue, Dry Eye
Not yet recruitingObservational study
Exploration Strategies in Night Vision Sensors
Visual Acuity
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 RLRL device in people with Asthenopia and Visual Fatigue, run by The Hong Kong Polytechnic University at 1 site in Hong Kong.
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 3 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 24 Sep 2025. 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 Hong Kong. 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?
change in the asthenopia questionnaire scores (time frame: at 2 weeks and 1 month compared to baseline). 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 NCT06745661, which also lists 1 linked publication.
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 24 Sep 2025.