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Biomedical subjects

F Dannheim

Publications and source records attributed to F Dannheim.

32 records · Page 2Linked to original sources
PubMed1981

VER analysis of the chiasmal syndrome.

In the evaluation of chiasmal syndromes the efficiency of VER analysis could be enhanced by separate stimulation of the temporal and nasal half of the visual field. The report is based on data of 27 patients with compressive chiasmal lesions. VER findings have been correlated with the visual fields meticulously plotted with a Tuebingen perimeter and/or an Octopus computer perimeter. Alterations in both parameters have been graded in three groups. The degree of alteration correlated fairly well for both test procedures. Not only was a reduction of VER amplitude observed for the affected hemifield, but a latency delay as well. A discrete damage in the nasal hemifield may be detected even earlier by means of VER half field analysis than by conventional subjective perimetry.

Adenoma↗
PubMed1978

[Laser lesions of the anterior segment of the rabbit eye. Studies of cornea, iris, lens and sclera using an argon, ruby and YAG-laser].

The anterior segment of the eye of 100 rabbits was exposed to radiation from Argon, Ruby and YAG lasers. The healing process of liminal and supraliminal lesions was evaluated histologically. The iris is the most sensitive tissue for all three lasers (threshold radiant exposure, Argon: 0.004 kJ/cm2, Ruby: 0.01 kJ/cm2, YAG: 0.05 kJ/cm2). Higher energies necessary for lesions in the transparent media were available only with the Argon and YAG lasers. The Argon laser failed to produce lesions in the lens, and threshold radiant exposure for the central cornea was 8 kJ/cm2. The thresholds for YAG lasers lesions in the central cornea and lens were of the same magnitude. The marked absorption of energy by the iris may lead to an accumulation of heat, resulting in lesions of adjacent tissues or a reduction of threshold for those lesions: The threshold in the peripheral cornea was ten times lower than in the center with the Argon laser, four times lower for the YAG laser. The thresholds for Argon and YAG laser lesions in the peripheral sclera lay between the thresholds for the iris and for the peripheral cornea. A safety standard for the anterior segment of the eye should be based on the lowest threshold (Argon laser lesion of the iris). The application of a factor 100 results in a maximal permissible exposure of 40 mJ/cm2. The influence of the beam diameter could not be evaluated.

Animals↗
PubMed1978

[Perimetry in glaucoma. Liminal and supraliminal stimuli (author's transl)].

With supraliminal, evenly moving targets absolute and relative glaucomatous visual field defects may be picked up as well as sensory alterations, even if static and kinetic perimetry seem to be normal. The method and their results in 53 eyes are described. Isolated findings in the nasal peripheral field are frequent and call for an accurate evaluation of this region in the search of early glaucomatous changes.

Adult↗
PubMed1977

[Perimetry in chiasmal syndrome -Liminal and surpraliminal stimuli (author's transl)].

The value of static and kinetic perimetry with white and colored stimuli in chiasmal syndrome seems to be equal. The presentation of evenly moving supraliminal targets allows for an evaluation of sensory disturbance. This procedure is even more subjective, variable and difficult to perform accurately. It may reveal, however, more discrete sensory pathology than conventional perimetry can do. Red is often better than other colors, spectral colors are better than pigment colors. The sector-shaped pattern of disturbance of sensation might relfect the arrangement of nerve-fibers in the optic chiasm.

Adenoma↗
PubMed1976

[Laser trabeculopuncture. III Experiments with rhesus monkeys].

Argon-laser trabeculopuncture was carried out on 7 rhesus monkeys. Perforation of the trabecular meshwork was possible with laser impacts of 100 msec, 4,200 mW and a beam diameter of 50 mum. Clinical and histological observations covered an interval of up to 15 weeks after coagulation. They revealed an obliteration of both the trabecular holes and the canal of Schlemm after a few days. Shorter pulse durations and higher energies might be helpful to improve the effectiveness, possibly assisted by a therapy with anti-inflammatory agents.

Animals↗
PubMed1975

[Anomaloscopic results in extrem-anomalous trichromats (author's transl)].

The results in 55 extreme deuteran and 34 extreme protan trichromats examined with the anomaloscope are reported, which make together about 9% of all red-green vision disturbances in a group of Federal Army relatives. Not only the deuteran but also the protan group make fewer mistakes with red colours as with green.

Color Perception↗
PubMedDate not supplied

Multicenter evaluation of tendency-oriented perimetry (TOP) using the G1 grid.

PURPOSE: The G1-TOP program is a short automated perimetric strategy which sub-divides the G1 grid of 59 points into four sub-grids. Each point is tested only once, but each patient's response is used to modify that particular point and the surrounding ones from the remaining sub-grids. This study compared the results of the G1-TOP program with the Standard Bracketing strategy. METHODS: Eleven participating institutions provided data from 213 patients (406 eyes). The main group consisted of 284 glaucomas and 55 glaucoma suspects. Other groups included 31 eyes with neurological disorders, 20 with chorioretinal lesions and 16 normal eyes. Mean age was 62.7 +/- 15.4 (range 14-88) years. All subjects had previous perimetric experience and visual acuity better than 0.5. Examination included G1-Standard Bracketing and G1-TOP testing, in interchangeable order, with the Octopus 1-2-3 perimeter. RESULTS: The correlation coefficient for mean defect (MD) was 0.95. Standard error (YX) for MD, square root of loss variance (LV) and individual thresholds were 1.86 dB, 1.29 dB, and 4.72 dB, respectively. Mean sensitivity values were similar (difference 0.04 +/- 1.87 dB) (p>0.05). Mean duration for G1-TOP was 2.19 +/- 0.26 min, while G1-Standard Bracketing took 11.51 +/- 1.52 min (ratio 1/5.1, or a net reduction of 80.4%). The sensitivity of G1-TOP versus G1-Standard Bracketing was: glaucoma 77.1/78.5, glaucoma suspects 38.2/47.3, neurological disorders 87.1/87.1 and chorioretinal lesions 80.0/85.0. CONCLUSIONS: The G1-TOP program gave very similar results to G1-Standard Bracketing in only 20% of the time required by the standard strategy.

Adolescent↗
PubMedDate not supplied

Visual field indices for the nasal step: different calculation procedures and their correlation with the clinical classification of visual field defects.

We calculated normal values for the normal population of the Octopus G1 program (n = 836) and values for defective fields due to glaucoma and other diseases (n = 147) to determine indices for a nasal step in the interpretation of glaucomatous visual fields. We used different calculation procedures and correlated the results with the clinical evaluation of the visual field. All indices tested were able to detect and quantify nasal steps in defective fields and to separate them from normal findings (area under curve of Receiver Operating Characteristic curves 0.963 to 0.999). Indices calculated excluding sensitivity values of positions with the greatest distance from the horizontal meridian or weighting of sensitivity values according to their closeness to the horizontal meridian showed the best results (auc = 0.999). We can thus conclude that the calculation of an index for nasal step is a simple and effective adjunct to any interpretation system for visual fields.

Diagnosis, Computer-Assisted↗