A Randomized, Repeated-measures Study to Measure the Temporal Frequency Response of Ocular Accommodation After Sustained Near Viewing.
Rochester Institute of Technology
Summary
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.
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.
Eligibility
- Age range
- Up to 35 years
- Sex
- All
- 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 d…
Interventions
- OtherNear 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').
- OtherDistant 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').
Location
- Chester F. Carlson Center for Imaging ScienceRochester, New York