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OpenTrials
Completed

NCT Number: NCT07291856

Exploring the Impact of Dynamic Defocus Display Schemes on Ocular Health Indicators

The present study is designed to explore the effects of dynamic defocus display technology on ocular health parameters using rigorous scientific approaches. It further examines the mechanisms through which this technology alleviates visual fatigue, thereby providing robust clinical evidence to support its practical application and widespread adoption.

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Key information

Age range

20 year–40 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Beijing Tongren Hospitol,Capital Medical University

Beijing, Beijing Municipality, 100730, China

About this study

Research Content Recruit adults who meet the inclusion criteria and have long-term use of VDT (Visual Display Terminal) devices for the trial.

Compare the impact of different dynamic defocus modes on the visual fatigue symptoms of the subjects.

Analyze the mechanisms through which dynamic defocus modes alleviate visual fatigue.

Research Outcome Measures Primary Outcome Measures and Definitions Binocular Visual Function: A series of assessments of visual ability, including accommodative function (amplitude of accommodation, accommodative facility) and vergence function (near point of convergence, AC/A ratio).

Secondary Outcome Measures and Definitions Critical Flicker Fusion Frequency (CFF): To evaluate the degree of eye fatigue, with lower measured values indicating a higher degree of fatigue.

Visual Fatigue Questionnaire Score: To assess the subjective level of visual fatigue experienced by the subjects.

Refraction Results: To monitor changes in refractive status during the trial and evaluate the impact of different dynamic defocus modes on refractive state when using VDT devices at near distance.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

Adults aged between 20 and 40 years, regardless of gender;

Refractive anisometropia ≤2.5D and corrected visual acuity of 1.0 or above in both eyes;

Habitual long-term use of electronic devices with LED light sources, such as computers and smartphones;

Currently not using any other blue light protection products or having ceased the use of such products for at least 2 weeks;

No known visually significant ophthalmic diseases;

Willing to participate in the trial and having signed the informed consent form.

Exclusion criteria

Abnormal accommodative function or other visual function abnormalities (e.g., strabismus, amblyopia);

Severe dry eye or history of ocular medication use;

Acute or chronic ocular surface inflammation, keratoconus, history of ocular surgery (e.g., refractive surgery), systemic diseases, or other conditions (e.g., wearing orthokeratology lenses and using atropine);

Photosensitivity, history of epilepsy, etc.;

Individuals unable to cooperate with the examination.

Treatment and study plan

Dynamic Defocus Mode

Behavioral

Participants are required to complete a 50-minute video-watching task using a terminal display device that contains video content processed with different dynamic defocus modes. Specifically, participants will watch the same series of videos in different dynamic defocus modes. Participants will complete a total of 5 sets of video tasks (including the control group) in a random order.

Primary outcomes

  1. Binocular Visual Function(amplitude of accommodation)

    Time frame: Baseline (before intervention), immediately after the 50-minute video-watching task for each of the five sessions, totaling ten completions per participant.

    The amplitude of accommodation refers to the maximum amount of accommodative power that the eye can exert to focus on near objects, typically measured in diopters.

  2. Binocular Visual Function(accommodative facility)

    Time frame: Baseline (before intervention), immediately after the 50-minute video-watching task for each of the five sessions, totaling ten completions per participant.

    Accommodative facility, measured using a 2D flipper in cycles per minute (cpm), reflects the eye's ability to rapidly and efficiently change focus between near and far objects, indicating the dynamic functioning of the accommodative system.

Secondary outcomes

  1. Critical Flicker Fusion Frequency(CFF)

    Time frame: Baseline (before intervention), immediately after the 50-minute video-watching task for each of the five sessions, totaling ten completions per participant.

    To evaluate the degree of eye fatigue, with lower measured values indicating a higher degree of fatigue.

  2. Visual Fatigue Questionnaire Score

    Time frame: Baseline (before intervention), immediately after the 50-minute video-watching task for each of the five sessions, totaling ten completions per participant.

    The Computer Vision Syndrome Questionnaire (CVS-Q), which has been independently modified, comprises 16 response items. Participants will complete the questionnaire before and after the task to assess changes in ocular strain symptoms. By comparing the questionnaire scores obtained when using different dynamic defocus modes of the VDT devices, the effectiveness of dynamic defocus modes in alleviating subjective symptoms of ocular strain will be evaluated.

  3. Refractive error status

    Time frame: Baseline (before intervention), immediately after the 50-minute video-watching task for each of the five sessions, totaling ten completions per participant.

    The refractive error status of the subjects was determined using a combination of automatic refractometer and subjective refraction, with results expressed in diopters.

Other outcomes

  1. Optical Coherence Tomography Angiography

    Time frame: Baseline (before intervention), immediately after the 50-minute video-watching task for each of the five sessions, totaling ten completions per participant.

    Optical Coherence Tomography Angiography (OCTA) is a non-invasive imaging technique that provides detailed cross-sectional images of retinal and choroidal structures. It is particularly useful for evaluating the choroidal thickness, which can be measured precisely in micrometers.

  2. Multispectral refraction topography

    Time frame: Baseline (before intervention), immediately after the 50-minute video-watching task for each of the five sessions, totaling ten completions per participant.

    Multispectral Refraction Topography (MRT) is an advanced imaging technique used to map the refractive properties of the eye across multiple wavelengths. By analyzing the eye's refractive profile at different spectral ranges, MRT offers a comprehensive understanding of the eye's optical characteristics.

Sponsors and collaborators

Lead sponsor

Beijing Tongren Hospital

Other

Registry information

Important dates

Study start
2025
Primary completion
2025
Study completion
2025
First posted
Dec 18, 2025
Registry last updated
Dec 18, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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