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Biomedical subjects

J Flammer

Publications and source records attributed to J Flammer.

At least 19 recordsLinked to original sources
PubMed1992

A comparison of five methods for estimating general glaucomatous visual field depression.

The separation of local and diffuse visual field loss is important for evaluating the nature and extent of glaucomatous visual field damage. Here, five automated methods for estimating diffuse loss in glaucomatous visual fields (as measured with the Octopus G1 program) are compared. Four are taken from the published literature, and one is introduced in this investigation. It is shown that the new index (here called diffuse loss) provides the best agreement with a value determined using a more empirical approach.

Glaucoma↗
PubMed1992

Lens opacity: a population study.

Age-corrected normal values for the Opacity Lens Meter (OLM) 701 were established by measuring 1598 eyes of 799 healthy volunteers. This study revealed a remarkable age-relation for the normal values. The average readings of the OLM of the 30-year-old subjects were around 10 units whereas the average for the 65-year-olds was close to 20 units. The best fit of the opacity vs. age was a quadratic function. The interindividual variation was small in the young and quite large in the older population. The correlation between contralateral eyes was high (R = 0.93).

Adolescent↗
PubMed1992

[Significance of the peripheral visual field for diagnosis of glaucoma].

Investigated was the significance of semiquantitative tests of the peripheral visual field in glaucoma. For that purpose 793 visual fields of 793 glaucoma patients or glaucoma suspects and 338 visual fields of 338 normal controls (normal central 26 degrees--area) were analysed. Perimetry was performed with an Octopus 201 with the help of program G1, which tests 14 peripheral test locations. In the majority of the 455 glaucoma patients (pathological findings in the central visual field) the periphery was also disturbed. Much to our surprise however, the 338 glaucoma suspects (having normal central visual fields) showed the same frequency of peripheral visual field disturbance as the normals. This holds true for the total peripheral visual field, as well as for the individual test locations. Therefore it makes sense to limit perimetry in glaucoma patients to the central area, provided that the central area is quantitatively measured with an adequate testgrid.

Diagnosis, Differential↗
PubMed1992

Lupus anticoagulants/anticardiolipin antibodies in patients with normal tension glaucoma.

Ocular vascular occlusive disease resulting in severe retinopathy and/or post-thrombotic glaucoma has been extensively discussed in patients with lupus anticoagulant and/or anticardiolipin antibodies (LA/aCL). Inadequate circulation plays an important role in the pathogenesis of another ophthalmic entity--the normal tension glaucoma. We studied 22 patients with normal tension glaucoma (group I) and 23 with chronic open-angle glaucoma (group II) and compared them with a control group (n = 25, group III). LA, aCL, the aCL cofactor beta 2-Glycoprotein I, and other haemostatic parameters including factor VIII:C, von Willebrand factor, factors II, V, VII and plasminogen activator inhibitor were measured. Five out of 22 (22.7%) in group I, five out of 23 (21.7%) in group II and three out of 25 (12.0%) in group III had positive LA and/or aCL. These prevalences were not statistically significantly different. beta 2-Glycoprotein I was normal in all groups. No other parameters were significantly different between groups. These findings do not support the contribution of ocular microvascular occlusive disease, due to elevated aCL, in the pathogenesis of glaucomatous damage.

Aged↗
PubMed1992

Psychophysical mechanisms and treatment of vasospastic disorders in normal-tension glaucoma.

Vasospasms are inappropriate constrictions of small vessels leading to a variety of clinical pictures depending on the location of such spasms. Although the pathophysiological mechanism is not yet well understood, we know some factors able to provoke spasm in patients with appropriate predisposition like hemorrhage, coldness, emotional stress and others. Such vasoconstrictions provoke normally relative mild symptoms like cold fingers, or pain as in variant angina and in only very rare cases, to irreversible structural damage such as myocardial infarction. There is not much known about the involvement of the eye in vasospastic disorders. Retinal migraine is a known entity but occurs quite seldom. If one looks for it, one can often find (mostly reversible) visual field damage in patients with vasospastic disorders. This might be a sign of a reversible functional damage most probably due to a decreased circulation in the optic nerve head or the surrounding choroid. In most of these patients the optic nerve head looks normal, sometimes slightly pale. In patients with the so-called normal-tension glaucoma however, the prevalence of vasospastic disorders, is very clearly increased. This leads to the hypothesis that recurrent vasospasm in the eye may, in some cases, finally lead to structural damage, presenting itself phenomenologically as normal-tension glaucoma. Therefore treatment or selected normal tension glaucoma patients with calcium-channel-blockers is helpful, as has been proven in prospective studies.

Calcium Channel Blockers↗
PubMed1992

Nitric oxide and endothelin-1 are important regulators of human ophthalmic artery.

The vascular endothelial cells have the ability to modulate local vascular tone by releasing relaxing factors such as nitric oxide or the vasoconstrictor peptide endothelin-1. Although this regulatory system is found in all vertebrates, there is a great heterogeneity in the release of these endothelium-derived substances, from one organ to an other, between large and small vessels, and between different species. Therefore, observations made in certain vascular beds or animals do not necessarily apply to human ophthalmic circulation. The present study was designed to investigate endothelial mediators in the human ophthalmic artery. The results show that in the human ophthalmic artery, nitric oxide is released under basal conditions and that its production can be markedly stimulated by bradykinin, acetylcholine, and particularly histamine, which cause profound vascular relaxation. In contrast, endothelin-1 evoked potent contractions, which were unaffected by the calcium antagonist nifedipine. However, upon re-exposure of the blood vessels to the peptide, marked tachyphylaxis occurred. These findings demonstrate that in the human ophthalmic artery, endothelium-derived nitric oxide and endothelin are very potent modulators of vascular tone, suggesting that they play an important role in the regulation of local blood flow in the eye. Hence, endothelium dysfunction may represent a new pathogenetic mechanism in disease states associated with altered blood flow to the eye, such as diabetes, hypertension, and some forms of low-tension glaucoma.

Acetylcholine↗
PubMed1991

Influence of betaxolol and timolol on the visual fields of patients with glaucoma.

In a double-masked study, 40 patients with primary open-angle glaucoma were randomly assigned to treatment with betaxolol 0.5% or timolol 0.5% in both eyes twice daily. Visual fields and intraocular pressures were studied. Perimetry was performed with the Octopus G1 program two weeks after a washout period and three, six, 12, and 18 months after initiation of treatment. Both drugs reduced intraocular pressure. The reduction in intraocular pressure in the timolol-treated group was more pronounced than that in the betaxolol-treated group; the difference, however, was not statistically significant. In both treatment groups, the visual fields tended to improve during the first six months of treatment and remained stable or tended to deteriorate thereafter. The treatment effect on the visual field was better in the betaxolol-treated group than it was in the timolol-treated group (P = .041).

Aged↗
PubMed1991

Blood-cell velocity in the nailfold capillaries of patients with normal-tension and high-tension glaucoma.

We compared the capillary blood-cell velocity in the fingertips of 30 patients with high-tension glaucoma, 30 patients with normal-tension glaucoma, and 30 control subjects by nailfold capillaroscopy. There were no measurable differences in the morphologic findings. The blood-flow velocity, however, was reduced significantly in the patients with normal-tension glaucoma compared with the control subjects (P less than .05). This difference was especially pronounced after cold provocation (P less than .0005). After cooling, 25 of 30 patients with normal-tension glaucoma had a blood standstill of 12 seconds or more, whereas only three of 30 control subjects and four of 30 patients with high-tension glaucoma had a measurable blood standstill.

Adult↗
PubMed1991

The learning and fatigue effect in automated perimetry.

A visual field test was performed on 100 volunteers to study learning or fatigue effects during one session. The test was carried out with the help of the Octopus program J1, which measures the threshold 12 times at 3 test locations. In the majority of cases the sensitivity was quite stable during the session. We noted no difference between trained and untrained subjects or between normal and pathological eyes. However, patients with refractive errors, especially myopes, revealed a larger learning effect than did emmetropes.

Adolescent↗
PubMed1991

Fluctuation of the differential light threshold at the border of absolute scotomas. Comparison between glaucomatous visual field defects and blind spots.

The outcome of repeated measurements of the differential light sensitivity fluctuates slightly. This fluctuation can be markedly increased in glaucoma patients but has also been described at the border of the blind spot of healthy subjects. The question arises, therefore, whether in glaucoma this increase may be due to the fact that many test locations may touch the border of (detected or undetected) scotomas. This study compares the behavior of the threshold at the border of glaucomatous defects and blind spots. The threshold was measured with program F8 of the Octopus 201 (Interzeag, Inc, Schlieren, Switzerland) automated static perimeter. The results revealed that the borders of glaucomatous defects are less steep than those of blind spots, the fluctuation is largest just at the border of the scotomas in both groups, and that the fluctuation is significantly larger at the edge of glaucomatous defects than at the edge of blind spots of normal subjects.

Glaucoma, Open-Angle↗
PubMed1991

[Effect of betaxolol and timolol on visual fields in glaucoma patients].

In a prospective, randomized, double-masked study, primary open-angle glaucoma patients were treated twice daily with either betaxolol 0.5% or timolol 0.5%. Patients received a pretreatment baseline examination following a 2 week washout period; they were then examined after 3 and 6 months of treatment. Each examination included visual field measurements with an Octopus automated perimeter and intraocular pressure measurement. The visual fields of the betaxolol group showed on the average a pronounced tendency toward improvement (MD decrease of 2.05 dB); visual fields in the timolol group showed a slight tendency toward improvement (MD decrease of 1.56 dB). The difference between these 2 trends after 6 months was statistically not significant (p greater than or equal to 0.05, U-test). Both drugs lowered intraocular pressure, there was no significant difference between the two drugs (p greater than or equal to 0.05, U-test).

Betaxolol↗
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↗