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NCT Number: NCT07679048

Measuring How Quickly the Eye Focuses After Sustained Viewing of Close-up Images and Videos

In this experiment, subjects will view a cross pattern on the screen and be asked to focus their eyes on it. The cross pattern will look like it is moving towards and away from the eye in a back-and-forth motion. As the subjects focus their eyes on the shapes, the investigators will measure the focus of their eyes using a device called a wavefront sensor. This device uses infrared light to measure the optical properties of the eye in real time. Our goal is to find out how well the eye focuses before and after viewing images on a screen up close (25cm). Since many people spend a lot of time looking at a computer screen while at work or at school, it is important to understand how this affects the eye's ability to focus.

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Key information

Conditions

Distance Viewing Eye Diseases Myopia Prolonged Near Viewing Refractive Errors

Age range

18 year–35 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Chester F. Carlson Center for Imaging Science

Rochester, New York, 14623, United States

Location status: Recruiting

Location contact

Benjamin M Chin, Doctorate

CONTACT

[email protected]

8454534320

About this study

In this experiment, subjects will view a Maltese cross pattern on a display through a Badal relay. Subjects will be instructed to accommodate to the pattern while a focus-adjustable lens optically moves the display closer and farther in depth as a sinusoidal function of time. As they do so, the investigators will measure the wavefronts of their eyes using a Shack-Hartmann wavefront sensor. The investigators will measure the gain and phase of the accommodative response of the subjects' eyes. Measurements will be made before and after sustained viewing of images on a computer screen 25cm away.

Who can participate

Healthy volunteers accepted: Yes

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

Inclusion criteria

  • Between 18-35 years of age
  • Normal or corrected-to-normal (glasses/contact lenses) vision.

Exclusion criteria

  • Vision worse than 20/20 while wearing glasses / contact lenses.
  • Fragile or loose teeth (participants need to bite a piece of dental clay to stabilize their heads so that measurements can be taken from their eyes)
  • Current pregnancy (experiment requires sitting down without moving for stretches of time)
  • Heart disease
  • Personal/familial history of epilepsy

Treatment and study plan

Near viewing first

Other

In a given session of the experiment (1.5 hours), participants do 2 sets of accommodation tasks. One task happens after viewing a screen for 20 minutes at 25cm, and the other task happens after looking at a distant object (10m) for 20 minutes. In one intervention, the session is structured such that the screen is viewed first ('near viewing first').

Distant viewing first

Other

In a given session of the experiment (1.5 hours), participants do 2 sets of accommodation tasks. One task happens after viewing a screen for 20 minutes at 25cm, and the other task happens after looking at a distant object (10m) for 20 minutes. In one intervention, the session is structured such that the distant object is viewed first ('distant viewing first').

Primary outcomes

  1. Gain and phase of ocular accommodation

    Time frame: Each measurement takes 10 seconds. In the experiment, the investigators will take measurements over the course of approximately 1 hour.

    Ocular accommodation is the focusing response of the lens in the eye. When the stimulus viewed by the participant changes in distance, the eye automatically refocuses. The investigators measure this refocusing using a device called a wavefront sensor. The investigators are particularly interested in the gain of accommodation, which is the ratio of the amplitude of accommodation to the amplitude of sinusoidal changes in stimulus distance. The investigators are also interested in the phase of the accommodative response, which is related to the lag of the accommodative response.

Study contacts

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

Benjamin M Chin, Doctorate

CONTACT

[email protected]

8454534320

Sponsors and collaborators

Lead sponsor

Rochester Institute of Technology

Other

Collaborators

  • National Eye Institute (NEI)

Registry information

Official study title

A Randomized, Repeated-measures Study to Measure the Temporal Frequency Response of Ocular Accommodation After Sustained Near Viewing.

Important dates

Study start
2026
Primary completion
2026
Study completion
2026
First posted
Jul 1, 2026
Registry last updated
Jul 8, 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.

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