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Corneal electrodes useful for clinical electroretinography require topical anesthesia, interfere with vision, can abrade, and are not well accepted by most children and many adults. A low mass conductive thread, corneal (DTL) electrode is described and comparatively tested against the Burian-Allen electrode. The DTL electrode was found to have few of the(More)
Chronically implanted intraocular electrodes were used to stimulate visual cortical responses to current passage through the retina. Electrical current threshold for the light-adapted cat retina lies in the region of 30 to 100 X 10(-6) amps. for the conditions used. Dark adaptation caused a large threshold increase. Retinal excitability also decreased when(More)
Hereditary blindness in Rhode Island Red chickens was analyzed at various post-hatching stages by light microscopy and electrophysiological recordings. At the time of hatching the retina of affected chicks appeared morphologically normal and identical to that of control, non-affected chicks. Whereas the electroretinographic (ERG) response to light stimulus(More)
With the increasing use of the rat as an animal model for glaucoma and for the evaluation of neuroprotective treatments, there is a need for a sensitive test of retinal ganglion cell (RGC) function in this species. The aims of this study were to detect functional abnormalities of the inner retina in a rat model of high intraocular pressure (IOP) using the(More)
The visual acuities (i.e., visual thresholds for pattern detection) of four dogs under neuromuscular block were measured using visually evoked cortical potentials (VECP) and/or pattern-evoked retinal potentials (PERR). Stimuli were phase-reversing square-wave gratings with a mean luminance of 86 cd/m2 and 70% contrast. The mean of the VECP thresholds of two(More)
Several tests of visual function were applied to an abstaining user (10 years or more) group and a nonuser group carefully preselected to be free of clinical signs of eye disease. The groups were matched on several criteria. The results show that all findings from both groups are within established limits of normalcy. Small differences and trends were found(More)
Electrical signals in response to both diffuse flashes of light and phase-alternating spatial patterns were recorded from the eyes and from the occipital scalp of a subject with a traumatic unilateral (right) optic nerve section. Clinical examination disclosed a grossly normal right eye with no light perception, a Marcus Gunn pupil, and an atrophic optic(More)
PURPOSE To further understand a common veterinary anesthetic, propofol (2,6- di-isopropylphenol) and effects of infusion rates on the retinal neurons in Beagle dogs. METHODS Standard full-field blue xenon-flash stimulation elicited responses of dark-adapted eyes, which were recorded from dogs before and after a propofol infusion rate increase. RESULTS(More)
PURPOSE A redistribution of neurochemicals has been identified in the visual cortex of monkeys with laser-induced glaucoma. Examined were functional, structural, and neurochemical changes to the retina, optic nerve, and central visual system in a nonhuman primate model of optic nerve head (ONH) ischemia caused by sustained unilateral administration of(More)
Giant neural cell systems (dendrites, cell bodies, and axons) are present among more usual structures in the retina and optic nerve of the small whale (dolphin) Tursiops truncatus retina. Giant cell body dimensions range up to 75 microns in diameter. Nuclei of the cells are frequently larger (greater than 20 microns) than nearby ganglion, bipolar, and(More)