A Study of Full-Spectrum Screen Lighting for Reducing Screen-Related Eye Fatigue and Dry Eye

N/ANot Yet RecruitingNCT07706231

Zhongshan Ophthalmic Center, Sun Yat-sen University112 enrolled

Overview

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.

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.

Interventions

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.

Eligibility

Sex: ALLMin age: 18 YearsMax age: 35 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: 1. Age 18 to 35 years, male or female. 2. Average daily electronic screen exposure of at least 4 hours. 3. Near visual acuity at 40 cm of 0.5 or better, and able to complete the study 1. tasks and measurements stably. 4. Able and willing to provide written informed consent. Exclusion Criteria: 1. Presence of ocular inflammation or ocular disease. 2. History of severe systemic disease, neurological disease, or psychiatric disorder. 3. Use of dry eye or visual fatigue treatments, or contact lens wear, within 1 month before the study. 4. History of ocular surgery within the past 6 months. 5. Daily use of lenses with blue-light blocking, photochromic, polarized, filtering, or similar optical functions. 6. Professional background in ophthalmology or optical products. 7. Intake of caffeine or other stimulants within 4 hours before the study. 8. Best-corrected visual acuity (BCVA) less than 0.8. 9. Anisometropia of 1.00 diopter or greater, or astigmatism of ±2.00 diopters or greater. 10. Intraocular pressure (IOP) less than 5 mmHg or greater than 21 mmHg. 11. Non-invasive tear breakup time (NIBUT) less than 5 seconds in either eye. 12. Ocular Surface Disease Index (OSDI) score of 33 or greater.

Outcomes

Primary Outcomes

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.