Boris I Gramatikov
Wilmer Eye Institute, Johns Hopkins University School of Medicine, USA
Title: A computer system integrating central fixation detection and optical coherence tomography for pediatric applications
Biography
Biography: Boris I Gramatikov
Abstract
Optical coherence tomography (OCT) enables volumetric rendering and the generation of fundus images that precisely and register OCT images to fundus features. Yet, there is little data about how a child’s retina develops. This limits
our knowledge of how diseases affect a child’s vision early in life and makes diagnosis of these diseases more difficult. The introduction of OCT to pediatric applications has been impeded by several factors, among them data acquisition and analysis speed, and difficulty in attaining stable fixation of the pediatric patient on a target over a period of time long enough to allow reliable analysis. The system described here integrates three major components: a computer-controlled video player that plays attention attracting movies and directs the subject’s fixation to a central point target; a retinal birefringence scanning subsystem for fast detection of central fixation by detecting the position of the fovea, and; an optical coherence tomography subsystem for acquiring 3D images from the retina (mainly in the foveal region). From a main menu, the operator selects a suitable video to be played by a small monitor in the visual field of the child under programmatic control. The software then starts the birefringence scanning system that scans the area around the fovea using polarized light, and in a double-pass configuration, analyzes the changes of polarization caused by the Henle fibers around the fovea. This allows fast detection of central fixation. The OCT system is instructed by the central software to acquire data if and only if central fixation is detected. This significantly reduces data redundancy and the time needed for analysis of the OCT data, while improving the overall reliability of the system. The idea is applicable to handheld devices.