RESUMEN
An early peak of the pattern reversal evoked potential with an implicit time between 30 and 50 msec, and an amplitude of 0.5-1 muv was demonstrated. The peak varies with the spatial frequency of the stimulus (checksize), and, the viewing condition (binocular vs monocular). Further study is being done to determine the origin.
Asunto(s)
Potenciales Evocados Visuales , Percepción de Forma , Reconocimiento Visual de Modelos , HumanosRESUMEN
The conditions of three siblings with concurrent retinitis pigmentosa and von Hippel tumors were evaluated. Their eyes showed the characteristic arteriolar attenuation expected in retinitis pigmentosa, except in the retinal sectors containing von Hippel tumors, where large feeder vessels supplied each tumor. Two of the siblings suffered further loss of vision as a result of large exudative retinal detachments associated with the von Hippel tumors. Both patients had satisfactory resolution of the retinal detachments following cryotherapy and laser therapy of their retinal tumors. The third sibling has a small retinal detachment that should te amenable to therapy. Visually handicapped patients require routine follow-up examinations to detect new diseases that may result in low of the remaining vision.
Asunto(s)
Angiomatosis/genética , Neoplasias del Ojo/genética , Enfermedades de la Retina/genética , Retinitis Pigmentosa/genética , Adulto , Angiomatosis/complicaciones , Neoplasias del Ojo/complicaciones , Neoplasias del Ojo/cirugía , Femenino , Humanos , Masculino , Linaje , Embarazo , Desprendimiento de Retina/complicaciones , Desprendimiento de Retina/genética , Desprendimiento de Retina/cirugía , Enfermedades de la Retina/complicaciones , Retinitis Pigmentosa/complicacionesRESUMEN
A patient who had ingested quinine as a suicide gesture was followed from 14.5 hr to 6 months with electrodiagnostic tests. The electroretinogram revealed early increased a-wave and decreased b-wave amplitudes, increased implicit times, and diminished oscillatory potentials. The electro-oculogram showed a decreased "light rise," and the pattern visually evoked potential was found to have an increased implicit time throughout the period of testing. These data indicate that there is an early direct toxic effect of quinine on the retinal cells.
Asunto(s)
Ceguera/inducido químicamente , Quinina/envenenamiento , Enfermedades de la Retina/inducido químicamente , Adulto , Electrooculografía , Electrorretinografía , Potenciales Evocados , Femenino , Humanos , Estimulación Luminosa , Enfermedades de la Retina/diagnóstico , Intento de SuicidioRESUMEN
A 25-year-old woman had no light perception in either eye 14.5 hours after ingesting 3.7 to 4.7 g of quinine. Fundus photographs showed mild venous distention and retinal haziness, but normal arteries. The electroretinogram, electrooculogram, and visual-evoked potential were all mildly abnormal. Two days after the patient ingested quinine, her visual acuity returned to 6/6 (20/20) with a markedly constricted visual field. The classic late fundus appearance of quinine toxicity, marked vascular narrowing, and disk pallor developed within six months. Visual fields remained constricted to 12 degrees with small temporal islands.
Asunto(s)
Ceguera/inducido químicamente , Quinina/envenenamiento , Campos Visuales , Adulto , Electrorretinografía , Femenino , Angiografía con Fluoresceína , Humanos , Enfermedades de la Retina/inducido químicamente , Enfermedades de la Retina/diagnóstico , Intento de Suicidio , Agudeza VisualRESUMEN
A survey of a college age population revealed that 8% could produce voluntary nystagmus. Seventy-nine per cent of this sample had relatives who could also produce it. A systematic investigation of the characteristics of voluntary nystagmus under a number of stimulus conditions showed that it resembles pendular nystagmus in waveform, and certain ocular oscillations, such as ocular flutter and opsoclonus, in frequency. The results indicate that voluntary nystagmus can be differentiated from other forms of nystagmus by its frequency, duration, and occurrence in individuals whose neuro-ophthalmological examination is normal. Voluntary nystagmus probably involves the "hold" mechanism of the cerebellar nuclei because of its frequency correspondence to ocular oscillations which result from a dysfunction in this anatomical area.
Asunto(s)
Nistagmo Patológico/diagnóstico , Adolescente , Adulto , Núcleos Cerebelosos/fisiopatología , Diagnóstico Diferencial , Electronistagmografía , Femenino , Humanos , Iluminación , Masculino , Nistagmo Patológico/epidemiología , Nistagmo Patológico/genética , Nistagmo Patológico/fisiopatología , Estimulación Luminosa , Factores de Tiempo , Estados Unidos , Campos VisualesRESUMEN
The characteristics of eye movements elicited by auditory stimuli, the audio-ocular response (AOR), differ from those made in response to visual stimuli. Their latencies are longer, their accuracies slightly worse, and their velocities slower. In addition, AOR latencies decreased with increasing stimulus eccentricity; this is opposite to the latency variation of visually evoked saccades.
Asunto(s)
Estimulación Acústica , Movimientos Oculares , Estimulación Luminosa , Adulto , Femenino , Humanos , Masculino , Tiempo de ReacciónRESUMEN
Berlyne's stimuli were presented in a stereoscope to test his hypothesis that Ss prefer the more irregular member of a pair of stimuli. 32 Ss, screened for normal acuity and phorias, were tested. Contrary to Berlyne's hypothesis and consistent with earlier stereoscopic studies, Ss tend to report more frequently the less irregular member of a pair of stimuli. These data can be explained by an information-conflict model; however, the clearest implication of this study was that experiments concerned with familiarity of stimuli should be qualified by the method.