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Biomedical subjects

J Flammer

Publications and source records attributed to J Flammer.

At least 181 records · Page 10Linked to original sources
PubMed1991

[Ocular vasospasm. 1: Functional circulatory disorders in the visual system, a working hypothesis].

Patients with normal-tension-glaucoma and with visual field defects of non-known origin, often suffer from mild vasospasm in the fingers. The observation often be provocated by coldness or emotional stress and that these defects can very often be reduced by a treatment of the vasospasm led to the hypothesis that a functional dysregulation of the circulation in the visual system might occur.

Arousal↗
PubMed1991

Systemic hypotension: a risk factor for glaucomatous damage?

Four glaucoma patients with rapid progression of visual field damage and excavation of the optic nerve head despite normal or well-controlled intraocular pressure had one factor in common: low systemic blood pressure. Furthermore, when monitored during 24 h, a sustained blood pressure drop during sleep was always observed. Systemic hypotension, therefore, might be a significant risk factor for glaucomatous damage. The authors recommend measuring the blood pressure frequently in such patients, especially at night.

Adrenergic beta-Antagonists↗
PubMed1991

Octopus program G1X.

The glaucoma program G1 is widely employed by Octopus users. In addition to a specific distribution of test locations, its main advantages are the quick comparison of results with normal values and an easy follow-up. The program, however, is relatively time consuming and, therefore, tiring for some patients. For this reason, the program was modified to 'G1X'. This program is interruptable at any time and provides information, including statistical analysis based on the available data. The test sequence is rearranged in accordance with the importance of the information. The available information, including the confidence limits, is continuously calculated and presented on the screen of the Octopus 1-2-3 during the test procedure. This provides the possibility of adapting the measurement to the patients and their state of health. The principal features as well as clinical applications are described.

Glaucoma↗
PubMed1991

[Ocular vasospasm. 4: Clinical examples].

The presumed ocular vasospasms provoke a variety of symptoms. Out of the large spectrum, two typical cases are described. The first case is a patient that developed visual field defect under psychological stress conditions. A drug therapy relieved the patient from the symptoms. The second case is a patient with a normal-tension-glaucoma. The treatment of the vasospasm improved the visual field markedly.

Adult↗
PubMed1991

Endothelium-dependent regulation of vascular tone of the porcine ophthalmic artery.

The endothelium produces relaxing and contracting substances, among them nitric oxide and endothelin. The role of the endothelium was investigated in the regulation of vascular tone in isolated porcine ophthalmic arteries suspended in a myograph system for isometric tension recording. In quiescent arteries with endothelium, the inhibitor of nitric oxide formation from L-arginine, L-NG-monomethyl arginine (L-NMMA), evoked endothelium-dependent contractions which were reversed by L-, but not D-arginine. In arteries contracted with serotonin, bradykinin evoked potent endothelium-dependent relaxations; L-NMMA markedly reduced the sensitivity but not the maximal response. Acetylcholine caused relaxations in preparations with endothelium but contractions in those without endothelium; L-NMMA prevented the relaxations and unmasked the contractions. The relaxations to the nitrovasodilator SIN-1 were more pronounced in preparations without than with endothelium. In quiescent arteries, quick stretching evoked endothelium-dependent contractions which were prevented by indomethacin. Endothelin-1, serotonin, and norepinephrine evoked concentration-dependent contractions with pD2 values of 8.1 +/- 0.1, 6.9 +/- 0.1, and 5.9 +/- 0.1, respectively. Removal of the endothelium markedly augmented the contractions induced by serotonin but not endothelin and norepinephrine. Thus, the endothelium profoundly affects vascular tone of the porcine ophthalmic artery. Endothelium-derived nitric oxide is released both under basal conditions and after stimulation with acetylcholine and bradykinin. It may play an important protective role in the circulation against vasospasm.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

The transparency of the lens: a comparison between diabetic and non-diabetic patients.

The transparency of the lens of 485 eyes of 266 healthy volunteers were compared with 143 eyes of 83 diabetic patients. All the patients had well controlled diabetes. The transparency of the lens was measured with the opacity lensmeter 701. The concept of the instrument is based on the measurement of scattered light. The result revealed a similar transparency of the lenses of diabetic patients in relation to the normal volunteers. There was only a slight, and statistically not significant trend in the older age group versus a greater opacity for diabetic patients.

Adolescent↗
PubMed1990

[The Opacity Lens Meter 701: clinical experiences].

The quantitative influence of cataracts on visual fields was studied in 11 patients before and after cataract extraction with intraocular lens implantation. Lens opacity, measured with the Opacity Lens Meter 701, correlated closely with the visual field changes. Measurement of stray light backscattered from the cataractous lens permits quantitative prediction of the influence of cataract on the visual field.

Aged↗
PubMed1990

Evaluation of visual fields by ophthalmologists and by OCTOSMART program.

The introduction of Goldmann perimetry standardized measuring conditions as much as possible. In spite of this, it had been possible for the perimetrist to influence the results of perimeter measurements. The introduction of computer-controlled perimetry, however, has largely eliminated the influence of the investigator on perimetry results. Nevertheless, the interpretation of a perimetric result in the everyday clinical situation is still extensively subjectively coloured and is liable to vary, depending on the doctor carrying it out. The OCTOPUS Program G1 was introduced a few years ago and used above all for glaucoma. This program greatly simplified visual field assessment thanks to its visual field indices. The indices make it possible to compare visual field results with those of a normal population. The present introduction of the OCTOSMART program represents a further step forward. This program analyses measured visual fields with the aid of standardized, statistical criteria based on a large, normal value study. This analysis standardizes and thereby simplifies the interpretation of visual field results. This study compares the outcome of the OCTOSMART program with visual field interpretations by eye doctors.

Evaluation Studies as Topic↗
PubMed1990

Do vasospasms provoke ocular diseases?

Vasospasms in the eye are often combined with digital vasospasms, as can be diagnosed with a nailfold capillaroscopic local cooling test. In 16 patients with a history of cold hands and feet the presence of peripheral vasospasms without any underlying disease was demonstrated by means of nailfold video-capillaroscopy. These patients showed the phenomenologic diagnosis of low-tension glaucoma with visual field defects characteristic of glaucoma even though intraocular pressure above 21 mmHg was excluded. The visual field defects were not homonymous, indicating a prechiasmal location of the vascular disturbance. Ocular vasospasms cause visual field damage that can be aggravated or provoked by cooling one hand in cold water and that often improves after treatment with the calcium channel blocker nifedipine. The results suggest that vasospasms not only are present in Raynaud's disease, migraine, and Prinzmetal's variant angina but also may be an important factor in the genesis of low-tension glaucoma. This is a new finding and may be related to a general vasospastic syndrome.

Adolescent↗
PubMed1990

[Normal-pressure glaucoma].

Normal tension glaucoma is defined as a clinical condition in which the optic nerve head is pathologically excavated and the visual field is disturbed, although the intraocular pressure is in the normal range. The following pathogenetic factors are considered responsible: too high IOP (even lying within the normal range) and primary circulatory disturbances, such as arteriosclerosis, systemic hypotension, orthostatic hypotension, hyperviscosity and functional vasospasms. The purpose of a clinical evaluation is to define the most important damaging factors for the individual patient. Accordingly, the therapy is directed towards the possible factors involved. Practically, this can mean: additional lowering of the intraocular pressure, increasing the blood pressure, lowering the blood viscosity and treating the vasospasms.

Glaucoma↗
PubMed1990

[Automated perimetry].

Today the automated perimetry is worldwide often applied. Beside ophthalmologists, other specialists are increasingly faced with this matter. For this reason some basic aspects are described such as: "differential light sensitivity, "decibel-scale", "strategies", "fluctuations" and so on. Different possibilities to present test results as well as some new features of automated perimetry are described here.

Glaucoma↗
PubMed1989

Increase of the short-term fluctuation of the differential light threshold around a physiologic scotoma.

Because determination of the differential light threshold of a visual field is a psychophysiologic test, the results can be subject to variation. This scatter measured during a single examination is usually called the short-term fluctuation. Increases of the short-term fluctuation were thought to occur primarily in abnormal visual fields; however, we found an increase of the short-term fluctuation in normal visual fields when the measurements were made at the border of a physiologic scotoma, such as the blind spot. These results suggest that an increase of the short-term fluctuation may be mainly related to measurements done with any static perimeter at the border of a depression of the island of vision.

Adult↗
PubMed1989

Puptrak 1.0--a new semiautomated system for pupillometry with the Octopus perimeter: a preliminary report.

A provisional, semiautomated version of a system for automated testing of the afferent pupillary reflex with perimetric methods under controlled conditions is described. The target projected onto the perimeter cupola is used as the stimulus for triggering the pupillary response. In a modification to the Octopus 201, the pupil is illuminated by two IR LED diodes, while the pupillary responses are recorded by the onboard IR sensitive TV camera built into the perimetric unit. Measurements of the pupillary area as a function of time and stimulus luminance have been performed and have resulted in consistent results. Here, one perimetric program, working with stimuli above the threshold for the afferent pupillary light reflex is described. The present setup works with system-specific software and standard hardware, the central data processing unit being a desk-top computer (IBM PC AT-03). The mating of an automated pupillary measuring unit to an automated perimeter may open the door for a more widespread evaluation of the value and the clinical application range of pupillary perimetry and may be of interest in other areas of visual and clinical psychophysics. The shortcomings of the present system, in particular insufficient temporal resolution and lack of full automation, are being removed at the present time.

Computer Systems↗
PubMed1989

The distribution of normal values in automated perimetry.

From 354 visual fields of 137 normal subjects, various components of variance were calculated separately for each test location of the Octopus automated-perimetry program J0. The method of component analysis of variance was used. The following components were analyzed: interindividual variation (variation of visual-field measurements in different subjects), long-term fluctuation (variation of different visual-field measurements in the same subject), differences between the right and left eyes and fluctuation within one visual field test in one subject, i.e., short-term fluctuation. The results show increased variations at the center relative to the paracentral area and a slight increase with eccentricity.

Adolescent↗
PubMed1989

[Sources of error in automated static perimetry].

Several sources of errors in interpreting computerized visual fields (learning effect, miotic pupil, sub-optimal refraction, dirty contact lenses, inadequate patient cooperation, anatomical obstacle, and choice of the wrong program) are described with the help of examples. Their identification should result in more reliable diagnoses.

Contact Lenses↗
PubMed1989

[Graphic and numerical presentation of visual field findings].

This article reviews the various ways in which visual field defects can be represented and the advantages and disadvantages of the most commonly used methods. In addition, the G1 analysis program, which will soon be available, is briefly described.

Computer Graphics↗