title: Detection of central fixation using short-time autoregressive spectral estimation during retinal birefringence scanning.
abstract: The manuscript reports on the implementation of autoregressive spectral estimation aimed at improving the accuracy of detecting short-lasting events in signals acquired by a retinal birefringence scanning device that was reported earlier. A signal consisting of two frequency components is generated, where each frequency is a multiple of the scanning frequency. One frequency is produced during central fixation, while another one prevails during off-central fixation. These components may be of a very short duration, presenting a challenge for the FFT to identify them with sufficient time- and frequency resolution. Autoregressive spectral estimation using the Burg algorithm provided a satisfactory solution, capable of reliably differentiating between the two frequency components (96 and 192 Hz) on signal segments of duration as short as 5 ms. The device and the signal analysis methods were developed originally with the purpose of checking for eye alignment and strabismus - a major risk factor for amblyopia. The method enables the technology to work with less-cooperative patients, such as young children. Other medical and non-medical applications are possible.
authors.affiliation: Ophthalmic Optics Laboratory, Wilmer Eye Institute, The Johns Hopkins University School of Medicine, 600 N. Wolfe St., Wilmer 233, Baltimore, MD 21287, United States. Electronic address: bgramat@jhmi.edu.
authors.forename: Boris I
authors.initials: BI
authors.lastname: Gramatikov
mesh_terms: D000465:Algorithms; D001718:Birefringence; D002648:Child; D004867:Equipment Design; D053483:Eye Movement Measurements / Q000295:instrumentation; D005403:Fixation, Ocular / Q000502:physiology; D006801:Humans; D008297:Male; D008962:Models, Theoretical; D012160:Retina / Q000502:physiology*; D012984:Software; D013997:Time Factors
keywords: Amblyopia; Autoregressive spectral estimation; Central fixation; Eye alignment; Retinal birefringence scanning; Strabismus