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.

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.

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.

In this clinical trial, the masking is applied to the participants and the study staff who conduct the assessments. The participants are single-blinded, meaning they are unaware of the specific dynamic defocus mode they are assigned to during the trial. This is to ensure that their subjective responses, such as those recorded in the visual fatigue questionnaire, are not influenced by their knowledge of the intervention.

The study staff who perform the assessments, including the measurement of critical flicker fusion frequency (CFF), accommodative function, and other ocular health indicators, are also blinded to the group assignments. This helps to prevent any potential bias in the data collection process, ensuring that the measurements are objective and reliable.

The randomization sequence and group assignments are managed by a third-party institution, which maintains the integrity of the blinding. Only after all data have been collected and the initial analysis is complete will the bl