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S.M. Kallenberger, C. Schmidt, H.–O. Carmesin; Eye Tracking Controlled Biofeedback System for Orthoptic Diagnosis and Fusion Therapy . Invest. Ophthalmol. Vis. Sci. 2005;46(13):2949.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose:Common Haploscopes used for orthoptic diagnosis require a manual input of the presented disparity. Besides they are restricted to the presentation of particularly prepared still images. For this purpose we developed a new biofeedback system enclosing a haploscope combined with an eye tracking system. Methods: A diplopic patient looks through LCD shutter glasses at a monitor. The movements of both eyes are recorded by two cameras. An eye tracking software determines the patient’s fixation points and his angle of strabismus. At the same time the position of the whole screen image is changed in the frequency of the shutter glasses: The image is shifted in the distance and the direction of the disparity between the calculated fixation points in order to make fusion possible. Thus fusion can be maintained automatically even when the angle of strabismus alters. For fusion training this is controlled by means of a negative feedback so that the disparity is gradually decreased according to the patient’s abilities. Diagnostic data are recorded permanently. Results: Initial investigations of patients with heterophoria or intermittent exophoria indicate a decrease of the subjective angle of strabismus by compensation and an increase of the fusional range. Conclusions: The developed device provides automatic measurement of the angle of strabismus and a biofeedback system for automatic adjustment of the required disparity. It provides several methods for diagnosis and makes an automated fusion training adapted to the patient possible. Any monitor contents, such as videos, TV or computer applications, can be used for fusion training or diagnostic purposes.
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