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Not yet recruitingNCT07844408RReyeUpdated Sep 28, 2026

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

An interventional study of Eye Exams and Ocular Biometry and Aberrometry in Myopia and Dry Eye Disease (DED), sponsored by Essilor International. Not yet recruiting at 1 site in France. Open to participants aged 18 Years to 35 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-09-28.

Sponsored by Essilor International · Not applicable, Interventional, and Basic science

Phase
Not applicable
Study type
Interventional
Enrollment
120
Allocation
Non-randomized
Ages
18 Years to 35 Years
Sex
All
01

Study summary

The goal of this observational study is to investigate the effects of eye fatigue induced by screen task on dry eye disease (DED) signs and symptoms, visual performance, and visual behavior in young adults with and without DED and with normal vision and myopia. The main questions it aims to answer are:

  • Does a screen task that induces eye fatigue affect dry eye signs and symptoms, visual quality, and visual behavior?
  • Are the effects of this screen task different in individuals with and without DED, and are they associated with myopia?

Researchers will compare participants with and without DED to determine whether they respond differently to a screen task designed to induce eye fatigue. They will also explore potential relationships between DED and myopia.

Participants will:

  • Attend two study visits.
  • Complete eligibility screening and realize visual and eye assessments.
  • Be classified as having or not having DED based on a questionnaire and clinical eye examinations.
  • Perform a screen task designed to induce eye fatigue.
  • Perform measurements before and after a screen task, including assessments of DED signs and symptoms, blinking behavior, eye movements, visual performance, and physiological responses with a smartwatch.
02

Conditions studied

  • Myopia
  • Dry Eye Disease (DED)

Keywords

  • Dry eye disease
  • Myopia
  • Contrast sensitivity
  • Screen use
  • Blink
03

Who can participate

Ages eligible
18 Years to 35 Years
Sexes eligible
All
Accepts healthy volunteers
Yes

Inclusion criteria

  • A willing participant who speaks French fluently, is willing to follow the protocol, is able to read and understand the informed consent form, and can give their free and informed consent;
  • Age between 18 and 35 years
  • Daily screen use of more than 4 hours
  • Monocular and binocular distance and near visual acuity of 0.1 logMAR or better (equivalent to 20/25 Snellen or 8/10) with best optical correction

  • Emmetropic groups:

    • Spherical equivalent (SE): -0.50 D \< SE ≤ +0.50 D
    • Regular astigmatism (cylinder) 0.75 D (absolute value)
    • Anisometropia 1.00 D

  • Myopic groups:

    • Spherical equivalent (SE): -5.00 D ≤ SE ≤ -0.50 D
    • Regular astigmatism (cylinder) 0.75 D (absolute value)
    • Anisometropia 1.50 D

  • Groups with signs and symptoms of DED:

    • OSDI-6 questionnaire score ≥ 4
    • NIBUT \<10 seconds

  • Groups without signs and symptoms of DED:

    • OSDI-6 questionnaire score \< 4
    • NIBUT ≥ 10 seconds.

Exclusion criteria

Exclusion Criteria:

  • Age \< 18 years
  • Pregnant or breastfeeding women
  • Individuals deprived of liberty by a judicial or administrative decision, and individuals hospitalized without consent under Articles L3212-1 and L3213-1 who do not fall under Article L1121-8, as well as individuals admitted to a healthcare or social institution for purposes other than research
  • Adults lacking legal capacity or unable to provide informed consent ;
  • Participants currently in the exclusion period of another research study;
  • All categories of individuals receiving special protection under French law are excluded from this research
  • Employees of Essilor International, Luxottica, GrandVision, or any of their subsidiaries.
  • Declared, untreated, and/or uncontrolled systemic disease that may affect vision (e.g., uncontrolled diabetes, uncontrolled hypertension);
  • Declared ocular disease, other than dry eye disease, with a significant impact on vision, such as visual field loss (e.g., glaucoma), reduced visual acuity, significant visual impairment in dim or bright environments (e.g., retinitis pigmentosa), corneal surface abnormalities including ectatic disorders (keratoconus, pellucid marginal degeneration), or corneal dystrophies (e.g., Fuchs dystrophy);
  • Declared autoimmune connective tissue disease or other condition known to cause dry eye disease (e.g., rheumatoid arthritis, rosacea, Crohn's disease, systemic lupus erythematosus, Graves' disease, Stevens-Johnson syndrome);
  • Active ocular or systemic allergy, or active ocular inflammatory condition such as keratitis, uveitis, blepharitis, etc.;
  • Declared neurological disorders, including a history of epilepsy, sensorimotor coordination disorders, ocular migraine, vestibular disease, or cerebellar disorders (e.g., balance disorders, nystagmus);
  • Binocular vision disorders such as strabismus, suppression, diplopia, amblyopia, or decompensated phorias associated with recurrent headaches, blurred or double vision, difficulty concentrating, or difficulties when frequently shifting focus between near and distance vision;
  • History of ocular surgery, refractive surgery, or ocular trauma;
  • Use of extended-wear contact lenses, rigid contact lenses, and/or orthokeratology lenses;
  • Prolonged wear of soft contact lenses (>12 hours per day);
  • Use of medications that may influence vision or interfere with study assessments (e.g., antidepressants, tranquilizers, antipsychotics, oral retinoids, or medications with atropinic effects);
  • Ophthalmic treatments, light therapy, or other treatments for dry eye disease within the past 3 months, with the exception of over-the-counter eye drops not requiring a prescription, such as hyaluronic acid-based lubricants.
04

Study design

Phase
Not applicable
Primary purpose
Basic science
Allocation
Non-randomized
Intervention model
Parallel assignment
Masking
None (open label)
Enrollment
120 participants (estimated)

Study arms

  • Experimental
    Myopes with presence of signs and symptoms of dry eye disease

    Device: Eye Exams · Device: Ocular Biometry and Aberrometry · Device: Wearing a Smartwatch · Device: Wearing Visual Correction · Device: Eye-Blinking Tests · Device: Retinal Examination · Device: Assessment of Signs and Symptoms of Dry Eye · Device: Assessment of Digital Eye Strain Symptoms · Device: Contrast Sensitivity Assessment · Device: Digital Eye Strain Task

  • Experimental
    Myopes without presence of signs and symptoms of dry eye disease

    Device: Eye Exams · Device: Ocular Biometry and Aberrometry · Device: Wearing a Smartwatch · Device: Wearing Visual Correction · Device: Eye-Blinking Tests · Device: Retinal Examination · Device: Assessment of Signs and Symptoms of Dry Eye · Device: Assessment of Digital Eye Strain Symptoms · Device: Contrast Sensitivity Assessment · Device: Digital Eye Strain Task

  • Experimental
    Emmetropes with presence of signs and symptoms of dry eye disease

    Device: Eye Exams · Device: Ocular Biometry and Aberrometry · Device: Wearing a Smartwatch · Device: Eye-Blinking Tests · Device: Retinal Examination · Device: Assessment of Signs and Symptoms of Dry Eye · Device: Assessment of Digital Eye Strain Symptoms · Device: Contrast Sensitivity Assessment · Device: Digital Eye Strain Task

  • Experimental
    Emmetropes without presence of signs and symptoms of dry eye disease

    Device: Eye Exams · Device: Ocular Biometry and Aberrometry · Device: Wearing a Smartwatch · Device: Eye-Blinking Tests · Device: Retinal Examination · Device: Assessment of Signs and Symptoms of Dry Eye · Device: Assessment of Digital Eye Strain Symptoms · Device: Contrast Sensitivity Assessment · Device: Digital Eye Strain Task

Interventions

  • DeviceEye Exams

    Participants undergo several visual examinations (visual function, visual refraction, visual acuity).

  • DeviceOcular Biometry and Aberrometry

    Participants complete ocular aberrometric and biometric measurements.

  • DeviceWearing a Smartwatch

    Participants wear an smartwatch to measure their physiological activity.

  • DeviceWearing Visual Correction

    Participants are equipped with appropriate vision correction through spectacle lenses.

  • DeviceEye-Blinking Tests

    Before and after a digital eye strain task, participants perform eye-blinking tests on a screen.

  • DeviceRetinal Examination

    Before and after a digital eye strain task, participants undergo a retinal examination.

  • DeviceAssessment of Signs and Symptoms of Dry Eye

    Before and after a digital eye strain task, participants' signs and symptoms of dry eye are assessed.

  • DeviceAssessment of Digital Eye Strain Symptoms

    Before and after a digital eye strain task, participants assess their symptoms of digital eye strain.

  • DeviceContrast Sensitivity Assessment

    Before and after a digital eye strain task, participants perform contrast sensitivity tests.

  • DeviceDigital Eye Strain Task

    Participants perform a 30-minute task designed to induce digital eye strain. During this task, eye movements, including blinking behavior, saccade and fixation behavior, are recorded by an eye tracker.

05

What researchers measure

Primary outcomes

  1. Contrast Sensitivity at Different Spatial Frequencies (logMAR)

    Contrast sensitivity test: Participants are asked to identify patterns (such as stripes or letters) that become increasingly difficult to see

    Time frame: From enrollment to 7 days after enrollment: Before and after a digital eye strain task

  2. Non-Invasive Tear Breakup Time (NIBUT) (seconds)

    Measurement of tear film stability by assessing the time it takes for the tear film to begin breaking up after a blink. Shorter times indicate a less stable tear film and may suggest dry eye disease. Measured with the IDRA instrument.

    Time frame: From enrollment to 7 days after enrollment: Before and after a digital eye strain task

  3. Visual Acuity (logMAR)

    Measurement of the clarity and sharpness of vision using the logMAR scale. Lower logMAR values indicate better visual acuity and the ability to see finer details.

    Time frame: At day 1: At baseline

  4. Area under the contrast sensitivity function curve (AULCSF)

    Contrast sensitivity test: Participants are asked to identify patterns (such as stripes or letters) that become increasingly difficult to see

    Time frame: From enrollment to 7 days after enrollment: Before and after a digital eye strain task

  5. Scores on the OSDI-6 questionnaires

    Assessment of dry eye disease symptoms and their impact on daily activities using the OSDI-6 questionnaire. It is the recommended questionnaire for dry eye disease. The questionnaire used six items. Each item is scored from 0 to 4 according to symptom frequency (0 = never, 1 = sometimes, 2 = often, 3 = mostly, 4 = constantly). The total score ranges from 0 to 24, with higher scores indicating more severe dry eye symptoms

    Time frame: At day 1: At baseline

  6. Scores on the IOSS questionnaires

    Assessment of the frequency and severity of symptoms related to dry eye disease using the IOSS questionnaire. The questionnaire used two items. Each item is scored from 0 (symptom never experienced) to 5 (very intense) with 1 (not intense at all). Higher scores indicate greater symptoms.

    Time frame: From enrollment to 7 days after enrollment: Before and after a digital eye strain task

  7. Blinking: frequency, duration, maximum interval, etc.

    Assessment of blinking behavior, including how often participants blink, how long each blink lasts, the maximum time between blinks, etc. These measures help evaluate visual fatigue and tear film stability during screen use. They will be measured with cameras and eyetracker.

    Time frame: From enrollment to 7 days after enrollment: Before, after and during a digital eye strain task

  8. Eye movements: saccades (amplitude, velocity, duration, frequency, latency, gain)

    Assessment of rapid eye movements (saccades), including their amplitude, velocity, duration, frequency, reaction time, and accuracy. These measures provide information about visual behavior and the effects of visual fatigue. They will be measured with cameras and eyetracker.

    Time frame: From enrollment to 7 days after enrollment: During a digital eye strain task

  9. Eye movements: fixations (position, duration, dispersion, number, frequency, stability, area)

    Assessment of eye fixations, including where and how long participants look at an object an the screen, as well as the stability and distribution of their gaze. These measures help evaluate visual attention, reading behavior, and the effects of visual fatigue. They will be measured with cameras and eyetracker.

    Time frame: From enrollment to 7 days after enrollment: During a digital eye strain task

Secondary outcomes

  1. Tear Meniscus Height (TMH) (millimeters)

    Measurement of the height of the tear reservoir along the lower eyelid. TMH provides an indication of tear volume, with lower values suggesting reduced tear production and risks of dry eye disease. Measured with the IDRA instrument.

    Time frame: From enrollment to 7 days after enrollment: Before and after a digital eye strain task

  2. Thickness of the lipid layer (nm)

    Measurement of the thickness of the outer oily layer of the tear film, which helps prevent tear evaporation. Thinner lipid layers may indicate tear film instability and an increased risk of dry eye disease symptoms. Measured with the IDRA instrument.

    Time frame: From enrollment to 7 days after enrollment: Before and after a digital eye strain task

  3. Ocular Redness Score

    Assessment of eye redness by evaluating the appearance of blood vessels on the surface of the eye. Higher scores indicate greater ocular irritation and inflammation, which may be associated with dry eye disease or visual fatigue. Measured with IDRA instrument.

    Time frame: From enrollment to 7 days after enrollment: Before and after a digital eye strain task

  4. Characteristics of the lipid layer (interferometry, colors, homogeneity, fringe pattern)

    Assessment of the quality and structure of the tear film's outer lipid layer. Parameters such as color patterns, uniformity, and interference fringes provide information about tear film stability and the risk of dry eye disease. Measured with the IDRA instrument.

    Time frame: From enrollment to 7 days after enrollment: Before and after a digital eye strain task

  5. Screen time since waking up (hours)

    Measurement of the total time spent using digital screens since waking up on the day of the assessment. This measure helps evaluate the potential impact of screen exposure on visual fatigue and dry eye disease symptoms.

    Time frame: From enrollment to 7 days after enrollment: At the start of each visit

  6. Weekly screen time (hours)

    Measurement of the average number of hours spent using digital screens each week across all devices. This measure helps assess long-term screen exposure and its potential impact on visual fatigue and dry eye disease symptoms.

    Time frame: At day 1: At baseline

  7. Score on the Digital Eye Strain Questionnaire

    Assessment of symptoms related to digital eye strain, such as eye discomfort, blurred vision, headaches, and visual fatigue. Each symptom is rated on a scale from 0 to 10, where 0 indicates no symptoms, 1 indicates very mild symptoms, and 10 indicates very severe symptoms. Higher scores indicate more severe symptoms.

    Time frame: From enrollment to 7 days after enrollment: Before and after a digital eye strain task

  8. Optical quality: Total optical aberration (total RMS, micrometers), High-order optical aberration (RMS HOAs and per order, micrometers)

    Assessment of the optical quality of the eye by measuring imperfections that affect image clarity. Total aberrations reflect overall optical distortion, while higher-order aberrations assess more subtle distortions that can reduce visual quality. Measured with a Pentacam AXL.

    Time frame: At day 1: At baseline

  9. Accommodative measurements: PPA (centimeters) or AA (diopters), Accommodative rock (cycles/degree)

    Assessment of the eye's ability to focus on near objects and rapidly switch focus between different distances. These measures provide information about visual flexibility, focusing performance, and visual fatigue. Measured with optometric instruments.

    Time frame: At day 1: At baseline

  10. Cardiac activity (ECG) (beats per minute, variability in ms/Hz, interval between beats, etc.)

    Measurement of heart activity, including heart rate, heart rate variability, and the time between heartbeats. These parameters provide information about physiological responses to stress, mental workload, and visual fatigue during the study. Measured with a smartwatch.

    Time frame: From enrollment to 7 days after enrollment: Before, after and during a digital eye strain task

  11. Electrodermal activity (EDA) (frequency of phasic responses, conductance-level and response.)

    Measurement of changes in skin conductance, including baseline levels and rapid responses to stimuli. These parameters reflect physiological arousal, stress, and cognitive workload, providing insight into the body's response to visual tasks and fatigue. Measured with a smartwatch.

    Time frame: Before, after and during a digital eye strain task

  12. Mitochondrial activity: autofluorescence score (FPF intensity, FPF heterogeneity)

    Assessment of mitochondrial function by measuring flavoprotein autofluorescence (FPF) in the eye. FPF intensity and heterogeneity provide indicators of cellular metabolic activity and oxidative stress, which may reflect changes in ocular health and visual fatigue. Measured with an OcuScience device.

    Time frame: From enrollment to 7 days after enrollment: Before and after a digital eye strain task

  13. Reading speed (number of words read per minute)

    Measurement of the number of words read per minute, providing an indicator of reading performance, and the potential impact of visual fatigue and dry eye disease on reading ability.

    Time frame: From enrollment to 7 days after enrollment: During a digital eye strain task

  14. Errors made during the digital eye strain task (number of actions not taken and actions taken incorrectly)

    Measurement of the number of mistakes made during the screen task. This outcome provides an indicator of attention, task performance, and the effects of visual fatigue and dry eye disease on accuracy.

    Time frame: From enrollment to 7 days after enrollment: During a digital eye strain task

  15. Biometry: Choroidal thickness (microns)

    Measurement of the thickness of the choroid. Measured with spectral domain optical coherence tomography (OCT B-scan)

    Time frame: At day 1: At baseline

  16. Biometry: Vascular density percentage (%)

    Measurement of the vascular density percentage of the retina. Measured with spectral domain optical coherence tomography (OCT B-scan). Used to evaluate retinal blood vessel perfusion and microvascular health.

    Time frame: At day 1: At baseline

  17. Biometry: Foveal avascular zone (mm²)

    Measurement of the size of the central retinal area devoid of blood vessels, located at the fovea. Measured with optical coherence tomography angiography (OCTA). This measure is used to assess retinal microvascular integrity.

    Time frame: At day 1: At baseline

  18. Biometry: Axial length (mm)

    Measurement of the distance from the anterior surface of the cornea to the retinal pigment epithelium along the eye's optical axis, expressed in millimeters. Measured using Pentacam AXL. This measure is used to assess ocular size.

    Time frame: At day 1: At baseline

  19. Biometry: Pupillary diameter (mm)

    Measurement of the diameter of the pupil, expressed in millimeters. Measured using Pentacam AXL under standardized lighting conditions. This measure is used to assess pupillary function.

    Time frame: At day 1: At baseline

06

Study locations

1 site
  • Center of Neurosciences and Medical Research Essilor International
    Paris, Paris 75012, France
07

Registry details

Key details

Study ID
NCT07844408
Lead sponsor
Essilor International
Responsible party
Sponsor
First posted
Sep 28, 2026
Start date
Oct 2026 (estimated)
Primary completion
Nov 2027 (estimated)
Completion
Nov 2027 (estimated)
Last update
Sep 28, 2026

Study contacts

Delphine Tranvouez-Bernardin
Contact
tranvoud@essilor.fr
+33 1 55 96 47 04

Oversight

Data monitoring committee
Yes
FDA-regulated drug
No
FDA-regulated device
No
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