Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0028738 (nystagmus)
 7,431 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Following responses to constant velocity and sinusoidally oscillating movements of the whole visual environment were examined in normal subjects wearing blinkers to obscure central vision or subjected to a photo flash to induce a central scotoma, in patients with central scotomas of pathological origin and in one patient with a central scotoma in an immobile eye which provided open loop testing. Good following and brisk nystagmus were produced in patients with central scotomas and subjects with flash scotomas; it was subjectively evident that the scotoma itself could be used as a target to generate open loop pursuit and augment peripherally induced following responses. Following responses in subjects with blinkers were weak, possibly reflecting that, in everyday life, eye movements induced by movements of the visual background have to be suppressed. Open loop responses were strong, suggesting that the periphery has the latent potential to mediate good following. The findings provide a unified explanation for the various patterns of optokinetic nystagmus.
 ...
PMID:Following eye movements on the absence of central vision. 46 20

We reviewed eight cases of congenital homonymous hemianopia to emphasize the features that may help the clinician to diagnose a congenital disease. The patients were usually unaware of the visual field defect. The hemianopia was usually congruous when incomplete and the opticokinetic nystagmus had a normal pattern. Associated congenital ocular and neurologic abnormalities were common. Clinically recognizable atrophy or hypoplasia of the optic disk was found in all but one of the patients. There was often a history of neonatal or gestational difficulties followed by emotional, behavioral, and learning problems without mental retardation.
 ...
PMID:Congenital homonymous hemianopia. 96 3

Nystagmic eye movements in response to selective optokinetic stimulation of different parts of the retina were studied in normal human subjects by two methods: 1. a digital computer controlled by the eye movement signal was used to generate an optokinetic display which stimulated only the peripheral retina, simulating a central scotoma, and 2. a single dot of 0.6 degrees in diameter was used as the stimulus during maintained forward gaze. The results show that stimulation of the central or peripheral retina alone can produce optokinetic nystagmus in man, and that essentially the same type of nystagmus is produced in both cases. The slow phase velocity of nystagmus evoked from the peripheral retina falls off rapidly with distance from the fovea but can be facilitated by attention. Results are compared with other findings and a possible explanation is offered for the observed variation in slow phase speed which occurs during constant velocity optokinetic stimulation.
 ...
PMID:Optokinetic nystagmus during selective retinal stimulation. 118

Prior research has suggested that two types of fast eye movements (FEMs) can be distinguished behaviorally. Foveating saccades respond to salient peripheral targets by directing the target image to the fovea. Non-foveating saccades include other FEMs such as nystagmus quick phase, saccades without visual stimuli and visually-directed saccades that direct target images to eccentric retina. Foveating saccades have a shorter initiation latency and are faster than non-foveating saccades. Following adaptation to central scotoma, patients tend to use preferred retinal loci for fixation (PRL). If PRL acquire the foveal characteristic of a retino-motor center then visually guided saccades would acquire the properties of foveating saccades. Using an objectively-calibrated 2-dimensional search coil, we measured saccades in response to salient, unpredictable targets. The saccades of normal observers were compared to the saccades of patients with long-standing macular scotomas. Although the saccades of patients consistently directed images to PRL, the saccades still had the latency and dynamic characteristics of non-foveating saccades. Moreover, the non-foveating saccades of patients were found to be less accurate than foveating saccades, showing a range effect (larger saccades undershoot with greater error than do smaller saccades). Apparently, patients with macular scotoma suppress rather than adapt a foveating saccade mechanism.
 ...
PMID:Saccade control without a fovea. 177

The features of optokinetic nystagmus (OKN) suppression were investigated in various kinds of visual disturbances including those of optical, retinal, higher cortical and psychogenic etiologies. A new OKN suppression device was developed, modifying the principle of Ohm. Objective visual acuities were calculated using the visual angle of OKN suppression dots which were arranged in 12 steps corresponding to the visual acuity from 0.03 to 1.0 as determined by Landolt's method. A total of 286 cases were tested. Results were classified into four types of coincidence between objective and subjective visual acuities. The first group showed equivalent acuities. Normal subjects, cases of corneal opacity, aphakia with intraocular lens implantation and functional amblyopia belonged to this category. In the second group, objective acuity could not be determined because of fixation disturbance due to cortical lesion. The subjective acuity better than the objective acuity was obtained in the third group which consisted of cases with macular hole, central serous retinopathy and optic neuritis with central scotoma. Disturbance of foveal fixation to the OKN suppression dot seemed to be the reason for this difference in the acuities. In the fourth group, the objective acuity was better than the subjective acuity. This occurred in cases of psychogenic visual disturbance and malingerer.
 ...
PMID:Objective visual acuity testing by optokinetic nystagmus suppression. 221 66

Optokinetic nystagmus (OKN) was elicited in humans by a horizontally moving grating covering the whole visual field. Selective stimulation of central or peripheral parts of the retina was achieved by partial masking or scotopic viewing conditions in normals; three patients with a unilateral central retinal scotoma were studied in addition. In all cases, the elimination of foveal stimulation was accompanied by a decrease in OKN slow phase velocity compared to whole field stimulation. Vertical masks with retinally stabilized edges were used to selectively occlude or stimulate central or peripheral sectors with a fixed retinal location. A central stimulus was always more effective than the complementary peripheral stimulus, until the central zone was narrowed down to a width of 5-10 degrees. This central dominance was found throughout the range of velocities (6-180 degrees/s) and spatial frequencies (0.05-0.5 cycles/deg) used. A horizontal central band of occlusion caused a smaller decrease of OKN than a vertical occlusion with the same width. Scotopic vision caused a uniform mild decrease in OKN gain throughout the velocity range, provided that the spatio-temporal frequency of the stimulus remained within the scotopic resolution range. The patients had a slightly lower OKN gain when viewing with the scotomatous eye than with the contralateral, normal eye. The normal slight preference for temporal-to-nasal motion was not accentuated by masking or scotopic vision in normal eyes, but was enhanced in the eyes with the pathological scotomata in two of the three patients. All responses were immediate; no slow build-up was seen under any condition.
 ...
PMID:Control of human optokinetic nystagmus by the central and peripheral retina: effects of partial visual field masking, scotopic vision and central retinal scotomata. 376 88

We experienced two cases of "Osteosclerosis" who were 12 and 15 year old sisters. Previous reported cases of this disease are 50 cases and among them only one patient was reported in Japan. Osteosclerosis seems to be inherited as an autosomal recessive trait. Parental consanguinity is also observed. The peculiar facies are evident in infancy, characterized by broad, flat nasal bridge, ocular hypertelorism and prognathic, broadened mandible. Commonly, they have cutaneous syndactylies in bilateral hands and feet, especially between the second and third finger and toe. Roentgenographically, hyperostosis with osteosclerosis can be observed in systemic bones, particularly the calvarium is greatly thickened. Since such a bony change occurs most severely at the base of the skull, important clinical symptoms of this disease are cranial nerve palsies resulting from obliterations of unilateral or bilateral several cranial nerve foramina. In many cases deafness due to progressive encroachment upon the middle ear cavities and auditory nerve canals appears early in infancy. Transient palsy of the facial nerve occurs somewhat later, and bilateral facial paralyses are usually permanent in adulthood. In some cases optic atrophy and visual field defect due to compression of the optic nerves are late complications. Other ocular symptoms are strabismus, nystagmus and exophthalmos. Anosmia and trigeminal nerve palsy are less common. Lower cranial nerve symptoms can not be noted but the reason is unclear. Chronic headache, convulsion and mental retardation are occasionally present. They are considered as a result from increased intracranial pressure due to progressive diminution of the cranial capacity. By same mechanism, several patients have died suddenly from impaction of the medulla oblongata in the foramen magnum in early adulthood. Then, some reporter puts emphasis on prophylactic opening of the foramen magnum in all adult cases.
 ...
PMID:[Sibling case of osteosclerosis with cranial nerve symptoms]. 629 11

The preferential looking (PL) technique, pattern visual evoked potentials (VEPs) and (simple) tests for visual field size were used to assess visual functions in 37 children with neurological disorders, ranging in age from 10 weeks to 15 years. PL acuities were obtained for 23 out of 32 patients tested (70%). Acuity was nearly always lower than normal, which often, but not always, was related to ophthalmological or neurological defects. Pattern VEPs were recorded in 7 patients. In 3 out of 4 patients, VEP 'acuity' was much lower than PL acuity, possibly due to spontaneous eye movements. One of two cortically blind children had positive pattern VEPs. Visual field defects were seen in 21 out of 23 children tested with a simple method using a pair of white balls. In only one-third of these, the field defects could have been predicted by the neurological and/or ophthalmological conditions. In several cases, field size appeared to be affected by spontaneous and/or latent nystagmus. A simplified perimeter has been found very useful with children from the age of 4 years onwards.
 ...
PMID:Behavioural and electrophysiological measures of visual functions in children with neurological disorders. 663 25

We found bilateral optic atrophy and visual field defects (paracentral scotoma and blind spot enlargement) in a worker who had been engaged in lead refining work in a lead refinery factory for 30 years. The worker is a 53-year-old Japanese male with no specific family and past histories. He complained of headache and vertigo after getting up in the morning for the past several years. He had several examinations in departments of psychiatry, otorhinopharyngolaryngology, neurosurgery and ophthalmology. Abnormal findings were not obtained by neurological examinations, electroencephalography, CT scanning for the head, Doppler test for jugular, vertebral and ophthalmic arteries, and equilibrium function (nystagmus) tests, except for labyrinthine deafness. Though the environmental conditions in this factory had been much improved recently, considerable high concentrations of lead were found till around 1965. Considering the results of hematological examinations for the past 30 years, it is clear that he had been affected by lead. We suspect that the causative relationship exists between lead exposure and optic atrophy and visual field defects.
 ...
PMID:[A case of optic atrophy of a lead worker (author's transl)]. 727 47

Neuro-ophthalmic manifestations are important in multiple sclerosis. Optic neuritis is a frequent harbinger of the disease, and is characterized by subacute painful visual loss, with disproportionate loss of color and contrast sensitivity, central or cecocentral scotoma, and an afferent pupillary defect. Visual recovery is the rule, but tests have been developed to detect most cases of recovered optic neuritis. Intraocular inflammation has come to be recognized as a frequent accompaniment of multiple sclerosis. Because of the predilection of multiple sclerosis for the infratentorial white matter, defects in eye movement control are common, particularly internuclear ophthalmoplegias and nystagmus.
 ...
PMID:Neuro-ophthalmology of multiple sclerosis. 774 86


1 2 Next >>