Skip to main content
OpenTrials
Not Yet Recruiting

NCT Number: NCT07671144

Visual Perception, Binocular Rivalry, and Fatigue-Related Individual Differences in Colour and Illumination Judgement

This observational study aims to characterise individual differences in colour perception and binocular rivalry. Participants will complete computer-based visual perception tasks, including a colour perception task and a binocular rivalry task. The study will first examine whether individuals show measurable differences in these perceptual responses. It will then explore whether these differences are associated with chronotype, sex, sleep-related measures, and subjective fatigue. The findings may help clarify how stable individual characteristics and daily physiological states relate to visual perception.

Not Yet Recruiting

Trial opening soon.

Get Notified

Key information

Conditions

Colour Perception Binocular Rivalry Color Perception

Age range

18 year–25 year

Sex eligibility

All sexes

Study type

Observational

Primary location

About this study

Colour perception and binocular rivalry both show variability across individuals. However, the extent to which these individual differences are stable and whether they are associated with personal or physiological factors remains unclear. This study will use behavioural visual perception tasks to measure individual differences in colour perception and binocular rivalry. Participants will complete a colour perception task and a binocular rivalry task, along with questionnaire measures related to chronotype, sleep, fatigue, and demographic characteristics including sex.

The primary aim is to determine whether measurable individual differences are present in colour perception and binocular rivalry performance. The secondary aim is to examine whether these differences are associated with chronotype, sex, sleep-related variables, and subjective fatigue. The study is observational and does not involve a clinical intervention, drug, biologic product, or medical device.

Who can participate

Healthy volunteers accepted: Yes

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

Inclusion criteria

  • Adults aged 18 years or older.
  • Normal or corrected-to-normal visual acuity.
  • Normal or corrected-to-normal binocular vision.
  • Normal colour vision, or no self-reported colour vision deficiency.
  • Able to understand the study instructions and provide informed consent.
  • Able to complete computer-based visual perception tasks and self-report questionnaires.

Exclusion criteria

  • Self-reported colour vision deficiency.
  • Uncorrected visual impairment or eye conditions that may interfere with visual perception tasks.
  • Strabismus, amblyopia, or other binocular vision problems that may interfere with binocular rivalry testing.
  • History of neurological disorders, photosensitive epilepsy, or severe sensitivity to flickering visual stimuli.
  • Current condition or medication that, in the investigator's judgment, may substantially affect visual perception, attention, or task performance.
  • Inability to complete the task procedures or provide valid responses.

Treatment and study plan

Computer-Based Visual Perception Tasks

Other

Participants will complete computer-based visual perception tasks, including a colour perception task and a binocular rivalry task. These tasks are used to measure individual differences in perceptual responses and are not intended as a clinical intervention.

Primary outcomes

  1. Mean colour-adjustment values on the colour perception task

    Time frame: Day 1 (single laboratory session)

    Colour perception will be measured using a computer-based colour adjustment task. Participants will adjust the appearance of a target object or stimulus, and outcome variables will include adjustment values in colour space, such as chromaticity, hue, saturation, or luminance-related measures, depending on the final task implementation. These measures will be used to characterise individual differences in colour perception.

  2. Mean perceptual dominance duration during binocular rivalry

    Time frame: Day 1 (single laboratory session)

    Binocular rivalry is measured with a computer-based dichoptic task in which a different image is presented to each eye. Perceptual dominance duration is the mean length of time, in seconds, that one stimulus remains exclusively visible before perception switches to the other. Longer mean durations indicate more stable, slower-switching rivalry.

  3. Mean alternation rate during binocular rivalry

    Time frame: Day 1 (single laboratory session)

    Binocular rivalry is measured with the same computer-based dichoptic task. Alternation rate is the mean number of perceptual switches between the two stimuli per minute of viewing. Higher alternation rates indicate faster perceptual switching between the two eyes' images.

Secondary outcomes

  1. Morningness-Eveningness Questionnaire (MEQ) score

    Time frame: Day 1 (single laboratory session)

    Chronotype assessed using the Morningness-Eveningness Questionnaire (MEQ). Total scores range from 16 to 86; higher scores indicate greater morningness (a stronger morning-type preference) and lower scores indicate greater eveningness.

  2. Pittsburgh Sleep Quality Index (PSQI) global score

    Time frame: Administered once, within 7 days before or at the single laboratory session (Day 1); the PSQI assesses sleep over the preceding 1 month.

    Sleep quality assessed using the Pittsburgh Sleep Quality Index (PSQI). The global score is the sum of seven component scores and ranges from 0 to 21; higher scores indicate worse sleep quality (a global score above 5 indicates poor sleep quality).

  3. Karolinska Sleepiness Scale (KSS) score

    Time frame: Day 1: assessed immediately before and immediately after the visual perception tasks, which are completed within a single session lasting up to approximately 1 hour.

    Subjective sleepiness/fatigue assessed using the Karolinska Sleepiness Scale (KSS), a single-item 9-point scale. Scores range from 1 to 9; higher scores indicate greater sleepiness. The pre-task to post-task change in KSS score may also be reported.

Study contacts

Contact information is provided by the study sponsor or research team.

Cehao Yu, PhD

CONTACT

[email protected]

+852 3400 3012

Junkai Che, Master

CONTACT

[email protected]

+852 9783 8643

Sponsors and collaborators

Lead sponsor

The Hong Kong Polytechnic University

Other

Registry information

Official study title

Characterising Individual Differences in Colour Perception and Binocular Rivalry and Their Associations With Chronotype, Sex, and Sleep

Important dates

Study start
2026
Primary completion
2026
Study completion
2026
First posted
Jun 26, 2026
Registry last updated
Jul 6, 2026

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.

Related clinical trials

Published trials that share one or more normalized conditions with this study.