John B Siegfried

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INTRODUCTION With a prevalence of 3-5%, amblyopia represents a major public health problem. Effective treatment depends on early detection, and a broad consensus of professional opinion supports vision screening of infants and young children. No single method of screening has been demonstrated to be superior in detecting amblyopia and all methods have(More)
Low amplitude high frequency wavelets have been demonstrated to be ubiquitous in the visual system of animals and are observed in the ERG of man. Wavelets have also been observed superimposed upon large slow waves obtained from electrodes on occipital scalp. Presently, the rather stereotypic wavelet repetition rate permitted the use of active analog filters(More)
With the use of a Maxwellian view optical system to present light flashes to the right eye, electroretinograms (ERGs) and visual evoked cortical potentials (VECPs) were recorded from normal subjects. The first 120 msec postflash onset was examined. A series of five VECP wavelets was recorded with implicit times of 50, 72, 82, 90, and 101 msec, at the(More)
PURPOSE To study the function of the parvocellular (P) and the magnocellular (M) visual systems with steady-state visual evoked potentials (VEPs) in anisometropic amblyopes. METHODS A matrix of isolated checks was superimposed on a steady background with different check sizes and temporal frequencies to form specific stimuli to preferentially activate the(More)
The relation between the amplitude of evoked brain potentials in man and the relative luminance of two flicker components of different color was determined. The function, which is U-shaped, has a minimum which occurs near the point of equal luminance as judged by the psychophysical method of flicker photometry.