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Purpose

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, we 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.

Conditions

Eligibility

Eligible Ages
Under 35 Years
Eligible Sex
All
Accepts Healthy Volunteers
Yes

Inclusion Criteria

  • We will recruit participants for inclusion who are adults in the age range of 18-35 years, because these are the ages at which people's eyes are able to focus at near distances.

Exclusion Criteria

  • Participants will be screened for having normal or corrected-to-normal (glasses/contacts) vision. Participants with vision worse than 20/20 will be excluded. People with fragile or loose teeth will be excluded because participants need to bite a piece of dental clay to stabilize their heads so that measurements can be taken from their eyes (too much head and eye movement disrupts the measurement). People who are pregnant, with heart disease, or personal/familial history of epilepsy will be excluded because some studies recommend against them viewing computer displays while sitting down for an extended period of time.

Study Design

Phase
N/A
Study Type
Interventional
Allocation
Randomized
Intervention Model
Crossover Assignment
Primary Purpose
Basic Science
Masking
None (Open Label)

Arm Groups

ArmDescriptionAssigned Intervention
Experimental
Near viewing first first 		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. There are two types of sessions: one in which the screen is viewed first ('near viewing first'), and the other in which the distant object is viewed first ('distant viewing first'). All participants do both sessions. However, in one arm, participants do the 'near viewing first' session first.
  • Other: Near viewing first
    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').
  • Other: Distant viewing first
    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').
Experimental
'Distant viewing first' first 		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. There are two types of sessions: one in which the screen is viewed first ('near viewing first'), and the other in which the distant object is viewed first ('distant viewing first'). All participants do both sessions. However, in one arm, participants do the 'distant viewing first' session first.
  • Other: Near viewing first
    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').
  • Other: Distant viewing first
    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').

Recruiting Locations

Chester F. Carlson Center for Imaging Science
Rochester, New York 14623
Contact:
Benjamin M Chin, Doctorate
8454534320
bmccis@rit.edu

More Details

Status
Recruiting
Sponsor
Rochester Institute of Technology

Study Contact

Benjamin M Chin, Doctorate
8454534320
bmccis@rit.edu

Detailed Description

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, we will measure the wavefronts of their eyes using a Shack-Hartmann wavefront sensor. We 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.

Notice

Study information shown on this site is derived from ClinicalTrials.gov (a public registry operated by the National Institutes of Health). The listing of studies provided is not certain to be all studies for which you might be eligible. Furthermore, study eligibility requirements can be difficult to understand and may change over time, so it is wise to speak with your medical care provider and individual research study teams when making decisions related to participation.