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Biomedical subjects

J Röver

Publications and source records attributed to J Röver.

At least 37 records · Page 2Linked to original sources
PubMed1982

[Spontaneous healing of a cataract with secondary glaucoma (author's transl)].

A 55-year-old man was referred to our clinic with a mature, swollen cataractous lens and a secondary phakolytic glaucoma. However, the patient refused to undergo surgery. Twelve years later he returned. Meanwhile the lens had been almost completely absorbed; visual acuity was 20/32 and there had been no severe damage to the optic nerve. The speed of absorption of the lens had evidently been sufficient to cure the secondary glaucoma rapidly.

Adult↗
PubMed1981

The amplitude of the c wave in the human ERG as a function of the luminous energy of the stimulus.

Variation of the stimulus intensity and duration over a wide range causes a change in amplitude of the c wave. If the energy of the applied stimulus is kept constant, however, stimuli of 0.05-4 s duration effected c waves that were nearly equal in amplitude. As patients consider shorter stimuli with higher intensities to be more comfortable in ERG recording, stimuli of a duration of 2-4 s seem most appropriate for clinical testing.

Adult↗
PubMed1980

Visual evoked potentials as an aid in evaluating brain dysfunction following concussional injury: an animal model.

Visual evoked potentials were recorded sequentially, using permanent epidurally implanted electrodes, before and after accelerating the heads of rabbits. The amplitude of VEP, recorded after lesioning, was diminished and recovery time was prolonged depending on the amount of acceleration and the extent of brain lesions found later in histological examinations. VEP reflected damage to the brain more precisely than EEG or somatosensory evoked potentials, thus giving values for judging the extent of lesions in patients with brain injuries.

Animals↗
PubMed1980

Macula and periphery: their contributions to the visual evoked potentials (VEP) in humans.

An alternating checkerboard pattern subtending a visual angle of 25 min arc is capable of eliciting remarkably high amplitudes of visually evoked potentials (VEP) outside a visual angle of 2.5 degree. These contributions cannot be neglected when evaluating a VEP response obtained with a larger field of stimulation. When the retina is consecutively stimulated by concentric frame-shaped stimuli, the algebraic sum of all single cortical responses augmented the cortical response obtained when stimulating the whole field simultaneously by approximately 30%. This finding may be explained by the inhibiting interactions within the receptive field organisation of the retina.

Evoked Potentials↗
PubMed1980

[Prognosis of vitrectomy].

Of 63 eyes on which vitrectomy was performed with a follow-up of at least six months 34 had an ERG with a b-wave of 50 muV or more preoperatively. Twenty-nine eyes had a b-wave of less than 50 muV. Twenty-six (76%) with an ERG > 50 muV, but only five eyes with an ERG < 50 muV had useful vision postoperatively. Of the eyes with an ERG <50 muV and without useful vision post-operatively, 75% were found intraoperatively to have a total retinal detachment. From these results it is concluded that the preoperative ERG findings are of great value for evaluating the prognosis of a vitrectomy.

Electroretinography↗
PubMed1980

ERG in amaurosis fugax, depending on the position of the body. A case presentation.

A woman, aged 57, reported a considerable loss of vision in her right eye within approx. 60s after lying down. She regained her vision in the upright position within approx. 90s. The Ganzfeld ERG, recorded in the upright position, showed a moderately reduced amplitude, but was entirely absent when recorded in the supine position, closely correlated to the subjective fading of the vision. Although all other clinical tests revealed no further hint to the cause of this remarkable amaurosis fugax, a temporary hypoxy of the retina due to circulatory deficiencies is suspected.

Blindness↗
PubMed1978

The registration of slow ERG potentials of the perfused extracorporeal bull's eye.

Enucleated bull's eyes were perfused with blood and ERG recorded, with special attention paid to the slow components. When the blood flow was interrupted, the ERG components vanished in the following order: b wave, c wave, off-effect (d wave), and a wave. When the perfusion was continued afterward, we saw a variation in the standing potential that hinted at the biochemical activities causing slow electrical potentials of the retina.

Animals↗
PubMed1978

Prenuclear paresis of homolateral inferior rectus and contralateral superior oblique eye muscles.

In a case of left inferior rectus paresis, it is demonstrated that the lesion must be prenuclear. On downward gaze, the left eye, although it reached the required target with a rapid saccade, drifted back towards the midline immediately afterwards. During the drift, several corrective saccades appeared. A dissociated "gaze paretic" nystagmus resulted. Synchronously, the right eye showed an incyclorotary nystagmus. We suspect a lesion of "tonic" fibers supplying the nuclear region of the left inferior rectus and the right superior oblique muscle.

Adult↗
PubMed1978

[Surgical or conservative treatment in orbital complications of sinus inflammations (author's transl)].

47 patients with orbital complications resulting from acute sinusitis have been treated at the Freiburg ENT Department during the last seven years. Acute ethmoiditis predominated in children, while pansinusitis was more common in adults. Previous sinus surgery did not prevent orbital complications arising from the same sinus. Orbital involvement was classified into periostitis, subperiosteal abscess and orbital cellulitis. According to clinical findings, 44.7% of the patients were managed conservatively. Prognosis was best in periostitis, whereas consersative treatment was unsafe in orbital cellulits. Children usually respond well to appropriate antibiotic coverage but the occurrence of common upper respiratory or anaerobic pathogens should be kept in mind.

Adult↗
PubMed1977

[The relationship of amplitude of visual evoked potentials to side length of rectangular stimulus pattern and to abruptness of stimulus alternation (author's transl)].

Cortical potentials evoked by viewing checkerboard pattern reversal stimuli as well as horizontal and vertical rectangular pattern reversal stimuli were recorded. The amplitude of the cortical evoked responses decreased with increasing side length of the rectangular pattern and decreasing velocity of the pattern reversal. Psychophysical and electrophysiologic findings are compared with these data and their clinical relevance is discussed.

Adaptation, Ocular↗
PubMed1976

[A canthi-skin electrode electroretinogram, independent of eye movements (author's transl)].

In order to avoid misinterpretation of ERG recordings taken with canthiskin electrodes, the potential deriving from the two electrodes was fed into a balancing amplifier that eliminated opposing voltages and amplified unidirectional voltages. During voluntary as well as nystagmus caused eye movements as well as those caused by nystagmus clearly distinguishable averaged ERG's were recorded.

Amplifiers, Electronic↗
PubMed1976

ERG of humans without C-wave.

Three out of 18 healthy persons investigated with the DC-ERG do not show a c-wave. By varying the adaptation levels and intensities of the stimuli four components in the human ERG can be isolated, the cone and rod late receptor potentials, the positive DC response, and a c-wave in most subjects. It is suggested that investigation of these components reveals a more detailed understanding of the pathophysiologic mechanisms in some retinal diseases.

Action Potentials↗