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

NCT07706231 | Not Yet Recruiting

• 1 other identifier: SIT2026005
• Study Type: interventional
• Target: 112
• Locations: 1 country
• Sites: 1

Brief Summary

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.

Conditions

Visual Fatigue; Dry Eye; Computer Vision Syndrome

Keywords

Visual fatigue; Dry Eye; Computer vision syndrome; Critical flicker fusion frequency; Full-spectrum

Outcome Measures

Primary Outcomes (1)

• 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.

  Baseline and immediately after completion of the approximately 2-hour standardized screen task

Secondary Outcomes (4)

• Change in Computer Vision Syndrome Questionnaire Score

  Baseline and immediately after completion of the approximately 2-hour standardized screen task

• Change in EyeFatigue Tracker Ocular Behavioral Parameters

  Baseline and immediately after completion of the approximately 2-hour standardized screen task

• Change in Keratograph 5M Ocular Surface Assessment

  Baseline and immediately after completion of the approximately 2-hour standardized screen task

• Change in Eye Dryness Score on the 0-100 Visual Analog Scale

  Baseline and immediately after completion of the approximately 2-hour standardized screen task

Study Arms (2)

Full-Spectrum Screen Bar Lighting

EXPERIMENTAL

Participants assigned to this arm will complete an approximately 2-hour standardized screen task in a controlled laboratory environment using a full-spectrum screen bar light (MB23001032H-1B) as task lighting. The screen task may include computer-based text processing, screen reading, or viewing specified video materials. Task content, duration, and completion requirements will be kept consistent with the control arm.

Device: Full-spectrum screen bar light

Brightness-Matched Control

PLACEBO COMPARATOR

Participants assigned to this arm will complete the same approximately 2-hour standardized screen task in the same controlled laboratory environment without using a full-spectrum screen bar light or any additional screen bar lighting. Screen brightness will be adjusted to match the brightness condition of the full-spectrum screen bar lighting arm. Task content, duration, and completion requirements will be kept consistent with the experimental arm.

Other: Brightness-matched screen task without screen bar lighting

Interventions

Full-spectrum screen bar light DEVICE

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.

Full-Spectrum Screen Bar Lighting

Brightness-matched screen task without screen bar lighting OTHER

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.

Brightness-Matched Control

Eligibility Criteria

• Age: 18 Years - 35 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Age 18 to 35 years, male or female.
• Average daily electronic screen exposure of at least 4 hours.
• Near visual acuity at 40 cm of 0.5 or better, and able to complete the study 1. tasks and measurements stably.
• Able and willing to provide written informed consent.

You may not qualify if:

• Presence of ocular inflammation or ocular disease.
• History of severe systemic disease, neurological disease, or psychiatric disorder.
• Pregnancy or lactation.
• Use of dry eye or visual fatigue treatments, or contact lens wear, within 1 month before the study.
• History of ocular surgery within the past 6 months.
• Daily use of lenses with blue-light blocking, photochromic, polarized, filtering, or similar optical functions.
• Professional background in ophthalmology or optical products.
• Intake of caffeine or other stimulants within 4 hours before the study.
• Best-corrected visual acuity (BCVA) less than 0.8.
• Anisometropia of 1.00 diopter or greater, or astigmatism of ±2.00 diopters or greater.
• Intraocular pressure (IOP) less than 5 mmHg or greater than 21 mmHg.
• Non-invasive tear breakup time (NIBUT) less than 5 seconds in either eye.
• Ocular Surface Disease Index (OSDI) score of 33 or greater.

Sponsors & Collaborators

• Zhongshan Ophthalmic Center, Sun Yat-sen University: lead

Study Sites (1)

Zhongshan Ophthalmic Center

Guangzhou, Guangdong, 510060, China

Location

Related Publications (4)

• Chen H, Ratanapakorn T, Sukonpatip M, Asawaphureekorn S, Thinkhamrop W, Wang X, Eungpinichpong W. Effects of yoga facial massage on computer vision syndrome and ocular motor function: A randomised controlled trial. Complement Ther Med. 2025 Dec;95:103270. doi: 10.1016/j.ctim.2025.103270. Epub 2025 Oct 22.

  PMID: 41135797 BACKGROUND

• Ide T, Toda I, Miki E, Tsubota K. Effect of Blue Light-Reducing Eye Glasses on Critical Flicker Frequency. Asia Pac J Ophthalmol (Phila). 2015 Mar-Apr;4(2):80-5. doi: 10.1097/APO.0000000000000069.

  PMID: 26065349 BACKGROUND

• Singh S, Downie LE, Anderson AJ. Do Blue-blocking Lenses Reduce Eye Strain From Extended Screen Time? A Double-Masked Randomized Controlled Trial. Am J Ophthalmol. 2021 Jun;226:243-251. doi: 10.1016/j.ajo.2021.02.010. Epub 2021 Feb 12.

  PMID: 33587901 BACKGROUND

• Lin JB, Gerratt BW, Bassi CJ, Apte RS. Short-Wavelength Light-Blocking Eyeglasses Attenuate Symptoms of Eye Fatigue. Invest Ophthalmol Vis Sci. 2017 Jan 1;58(1):442-447. doi: 10.1167/iovs.16-20663.

  PMID: 28118668 BACKGROUND

MeSH Terms

Conditions

Asthenopia; Dry Eye Syndromes

Condition Hierarchy (Ancestors)

Eye Diseases; Lacrimal Apparatus Diseases

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: OUTCOMES ASSESSOR
• Purpose: PREVENTION
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: July 9, 2026
• First Posted: July 15, 2026
• Study Start: July 20, 2026
• Primary Completion (Estimated): December 31, 2026
• Study Completion (Estimated): December 31, 2026
• Last Updated: July 22, 2026

Record last verified: 2026-07

Data Sharing

• IPD Sharing: Will not share

Locations

CN (1)