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Dynamic visual acuity using "far" and "near" targetsCONCLUSIONS: DVA may be useful for assessing the functional consequences of an impaired gaze stabilization mechanism or for testing the effectiveness of a rehabilitation paradigm. Because target distance influences the relative contributions of canal and otolith inputs, the ability to measure DVA at near and far viewing distances may also lead to tests that will independently assess canal and otolith function.

OBJECTIVE: To present and test a methodology that uses dynamic visual acuity (DVA) to assess the efficacy of compensatory gaze mechanisms during a functionally relevant activity that differentially measures canal and otolith function.

MATERIAL AND METHODS: The effect of treadmill walking at a velocity of 1.79 m/s on subjects' visual acuity was assessed at each of two viewing distances. A custom-written threshold determination program was used to display Landolt C optotypes on a laptop computer screen during a "far" (4 m) target condition and on a micro-display for a "near" (50 cm) target condition. The walking acuity scores for each target distance were normalized by subtracting a corresponding acuity measure obtained while standing still on the treadmill belt.

RESULTS: As predicted by subjective reports of relative target motion, the decrease in visual acuity was significantly greater (p < 0.00001) for the near compared to the far condition.
Document ID
20050219236
Acquisition Source
Johnson Space Center
Document Type
Reprint (Version printed in journal)
Authors
Brian T. Peters
(Wyle (United States) El Segundo, California, United States)
Jacob J. Bloomberg
(Johnson Space Center Houston, Texas, United States)
Date Acquired
August 23, 2013
Publication Date
September 2, 2004
Publication Information
Publication: Acta Oto-laryngologica
Publisher: Taylor and Francis
Volume: 125
Issue: 4
Issue Publication Date: January 1, 2005
ISSN: 0001-6489
e-ISSN: 1651-2251
Subject Category
Life Sciences (General)
Distribution Limits
Public
Copyright
Public Use Permitted.
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