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Biomedical subjects

F Dannheim

Publications and source records attributed to F Dannheim.

At least 19 recordsLinked to original sources
PubMed1990

The topographical relationship between optic disc and visual field in glaucoma.

The spatial relationship between anatomy and function in glaucoma was studied in 15 selected cases of focal damage. Based on planimetric data of the optic disc the anatomical site of damage was defined as the sector with the thinnest neuroretinal rim. Perimetric data were evaluated with regard to 21 regions of the 'Perimetric Nerve Fibre Bundle Map' (Weber & Ulrich 1990a). The site of damage was defined as those regions with at least 50% of depressed points. The site of the affected rim and the number of the corresponding Perimetric Nerve Fiber Bundles showed a linear correlation over a limited range of the superior and inferior pole of the disc. A 'functional disc map' could be established for 6 perimetric regions.

Glaucoma↗
PubMed1983

[Peritest].

Explore the source record for details and available documents.

Glaucoma↗
PubMed1982

The Peritest, a new automatic and semi-automatic perimeter.

The Peritest is a new automatic and semi-automatic (manual) perimeter for detection and limited assessment of visual field defects. It uses either multiple or single stimulus static perimetry. The lightsources are LED's. A total of 206 positions can be examined including the center; 151 positions inside 25 degrees-eccentricity. The programmes use a threshold-related gradient adapted suprathreshold (0.6) strategy. The results are printed on a special chart using non-interpolated grey scales for indicating local reduction of sensitivity. General and local reduction of sensitivity are separated. The progress of the examination can be followed on a LED-monitor. The reliability of the patient is measured. 70% of small early glaucomatous defects (that are only found by high resolution meridional static perimetry) were detected. Such defects are not usually detected by routine kinetic perimetry. More peripheral defects were detected (greater than 25 degrees) than by kinetic perimetry. Due to the relatively high number of stimuli the typical configuration of defects was satisfactorily demonstrated for defects of moderate size and larger. The duration of the examination varies from less than 4 min. for a semi-automatic examination of normal eyes to 10-20 min. for automatic examination of eyes with defects of moderate size (average 15 minutes for 206 positions).

Glaucoma↗
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↗