Biomedical subjects

J Flammer

Publications and source records attributed to J Flammer.

At least 145 records · Page 8Linked to original sources

PubMed1995

Influence of posture on the visual field in glaucoma patients and controls.

The intra-ocular pressure rises when body position is changed from sitting to supine. This phenomenon occurs to the same extent in healthy people and glaucoma patients. The purpose of this preliminary study was to determine the effect of posture on the visual field. Visual fields of 15 eyes of 12 normal-tension glaucoma (NTG) patients, 16 eyes of 11 high-tension glaucoma (HTG) patients and 30 eyes of 26 healthy controls were measured in the upright and supine positions with program G1X on an Octopus swivel-arm perimeter. The delta mean defect (delta MD), that is MDupright-MDsupine, was calculated for each patient and compared among study groups. Whereas visual fields improved in healthy controls (delta MD = +0.45 dB), glaucoma patients showed a slight deterioration of the visual field after changing position from supine to upright (HTG: delta MD = -0.25 dB, NTG: delta MD = -0.24 dB). The difference between HTG and controls, as well as between NTG and controls, was statistically significant (p < 0.002, Student's t test). These findings indicate that in some glaucoma patients the regulatory mechanisms for blood supply in the optic nerve head are insufficient.

Adult↗

PubMed1995

Visaline in the treatment of age-related macular degeneration: a pilot study.

Age-related macular degeneration (AMD) is the main cause of a reduction in visual acuity in patients over the age of 65 years. A positive influence of medical treatment (i.e. with vitamins and trace minerals) has been suggested but remains unproven. In this randomized, double-blind study, 20 patients in an early stage of AMD were included. Over a period of 6 months, 9 patients were treated with Visaline and 11 with a placebo. The effect of the treatment was not statistically different between the two groups, admittedly small in number, in terms of visual and retinal acuity, color vision, and contrast sensitivity. Despite the lack of such measureable differences, the patients' own subjective assessments, however, were much better in the Visaline-treated group. Due to the short duration of the observation time, we can not comment on a possible long-term effect.

Adrenergic beta-Agonists↗

PubMed1995

Perilimbal aneurysms of conjunctival vessels in glaucoma patients.

Aneurysms of the conjunctival vessels occur frequently. Such aneurysms have even been described in glaucomatous patients but their significance in this condition is not clear. Because they may be of clinical value in some conditions, the extent of perilimbal aneurysms of the conjunctiva was evaluated in 20 normal-tension-glaucoma patients, 20 primary open-angle-glaucoma patients, and 60 controls. The extent of these aneurysms was graded as follows: none (0), faint (1-2), moderate (3-5), and copious (> or = 6). The group frequencies of these categories were 5%, 25%, 10%, and 60% in normal-tension-glaucoma patients; 40%, 40%, 20%, and in primary open-angle-glaucoma patients; and 43%, 32%, 12%, and 13% in control patients, respectively. The incidence of copious perilimbal aneurysms of the conjunctiva was significantly higher in normal-tension-glaucoma patients than in primary open-angle-glaucoma patients and controls (P < 0.0001). Because local medication cannot account for the differences in relation to the control group and because glaucoma patients differed mainly in that normal-tension-glaucoma patients had vascular risk factors, the reason for our finding might be related to circulation problems.

Aged↗

PubMed1995

Quantification of optic nerve blood flow changes using magnetic resonance imaging.

PURPOSE: To evaluate the possibilities of magnetic resonance imaging (MRI) for quantification of pharmacologically induced changes in optic nerve microcirculation. METHOD: T2-weighted MRI sequences were used to image the eye, optic nerve, and frontal cortex in rats. Two sets of control images before and one set during Gd (DTPA) infusion were recorded. Blood flow values for two regions of the optic nerve (an anterior part, including the optic nerve head, and a more posterior part) and the frontal cortex were calculated by image analysis from the change in signal intensity, as already reported for cerebral blood flow. For each rat, a control experiment before drug administration and a second experiment 30 minutes after subcutaneous injection of either placebo (n = 7), timolol (n = 7), or SDZ GLC-756, a dopamine D-1 antagonist and D-2 agonist (n = 7), were carried out in a double-blind fashion. RESULTS: Mean basal blood flow values were found between 29.4 and 45.6 ml/100 g per minute in the anterior part of the optic nerve, 38.3 and 42.9 ml/100 g per minute in the posterior part of the optic nerve, and 68.0 and 75.0 ml/100 g per minute in the frontal cortex. Placebo and timolol did not cause significant changes. SDZ GLC-756 significantly increased blood flow by 238% +/- 65% in the anterior part and by 87% +/- 40% in the posterior part of the optic nerve. CONCLUSIONS: These results suggest that MRI provides quantification of optic nerve blood flow and that dopaminergic substances increase optic nerve blood flow.

Animals↗

PubMed1995

Local action of the renin angiotensin system in the porcine ophthalmic circulation: effects of ACE-inhibitors and angiotensin receptor antagonists.

PURPOSE: The renin angiotensin system and endothelium-derived substances are important regulators of the microcirculation. The authors studied the roles of angiotensins (Ang), angiotensin converting enzyme (ACE)-inhibitors, and Ang II-receptor antagonists in the porcine ophthalmic circulation. METHODS: Isolated porcine ciliary arteries were studied in myographs and the intact porcine eye in a perfusion system at 80 cm H2O perfusion pressure with Krebs-ringer bicarbonate solution (37 degrees C, 95% O2, 5% CO2). RESULTS: ACE-inhibitors enalaprilat and benazepril (both 10(-5) M) did not change ciliary vascular tone nor flow of perfused porcine eyes. However, enalaprilat or benazepril enhanced the relaxation of ciliary arteries to bradykinin (P < 0.02). In the perfused porcine eye, enalaprilat (10(-5) M) augmented vasodilation to bradykinin (P < 0.02). The bradykinin antagonist Hoe 140 (3 x 10(-7) M) prevented the relaxation of ciliary arteries to bradykinin (P < 0.001), but not to acetylcholine. In perfused eyes, Hoe 140 reduced the vasodilation to bradykinin (P < 0.01). Ang II (10(-8) to 10(-6) M) evoked a contraction of ciliary arteries and was more potent than Ang I. Enalaprilat abolished the effect of Ang I. The AT1-receptor antagonist, valsartan (10(-9) to 10(-5) M; 30 minutes) inhibited the response of ciliary arteries to Ang II, whereas the AT2-receptor ligand CGP 42112 B (10(-7) to 10(-8) M) was ineffective. In the perfused porcine eye, valsartan restored the decrease in flow to Ang II. CONCLUSIONS: Angiotensins play an important regulatory role in the porcine ophthalmic microcirculation through AT1-receptors. ACE-inhibitors prevents the effects of Ang 1 and augment endothelium-dependent relaxation to bradykinin, which releases nitric oxide through B2 receptors.

Angiotensin I↗

PubMed1994

Anterior chamber depth and pigment dispersion syndrome.

Pigment dispersion syndrome is thought to be the result of iris pigment abrasion by zonular packets. This condition primarily affects young males with myopia, perhaps because of deeper anterior chambers that make such pigment abrasion more likely. Males have been described to have larger eyes and deeper anterior chambers. This constellation, however, does not explain conclusively the predominance of males who have pigment dispersion syndrome. We, therefore, studied whether anterior chambers in males are deeper than those in females, not only in absolute measures but also relative to the axial length. Our results of 60 patients disclosed that men had not only significantly deeper mean absolute anterior chambers (men, 3.22 +/- 0.42 mm; women, 2.88 +/- 0.38 mm; P = .002) but also deeper mean relative anterior chambers (men, 13.54% +/- 1.66%; women, 12.45% +/- 1.2%; P = .013). No significant differences existed between genders with regard to lens thickness, extent of ametropia, and visual acuity. Thus, normal developmental differences between genders may predispose males for deeper anterior chambers and, consequently, for pigment dispersion syndrome.

Adult↗

PubMed1994

Normal visual fields measured with Octopus-Program G1. II. Global visual field indices.

To complement results from individual test locations, clinicians also evaluate indices, as they give a succinct overview of the visual field. This, however, requires exact knowledge of their variability. The present study was designed to determine normal interindividual variability of global visual field indices and incorporates a data base of a multicenter study performed with Octopus 201 perimeters using Program G1. The 824 fields thus obtained included 139 fields of 139 healthy volunteers who had undergone two previous visual fields and completed all three phases of program G1. The index mean sensitivity showed a significant and linear decrease with increasing age, 0.064 dB/year of life. The indices loss variance, corrected loss variance, and short-term fluctuation did not correlate significantly with age. Percentiles are given for these visual field indices. While within the limits of normal values provided by the manufacturer for these indices, these results suggest that visual fields with "borderline" values require further clinical investigation in reliable, experienced subjects. The results may help clinicians to better evaluate global visual field indices and, therefore, to detect loss of visual function earlier.

Adult↗

PubMed1994

Moderate exertion lasting only seconds reduces intraocular pressure.

Intense physical exertion is known to reduce intraocular pressure (IOP). However, the effect of physical exertion on IOP in the first few seconds after beginning exertion has not been studied previously. IOP was determined twice within 15 s in 32 healthy, young men. Seventeen performed six deep knee bends within 8-10 s preceding the second IOP measurement, while 15 did not. The mean reduction in IOP immediately after such brief and moderate exertion was 1.9 +/- 0.3 mmHg, compared with 0.8 +/- 0.2 mmHg in the control group. The difference between both groups was statistically significant. Thus, even moderate physical exertion may reduce IOP. As the relative decrease in IOP correlated with the relative increase in heart rate, the observed reduction in IOP after brief, moderate physical exertion may be due to sympathetic activity.

Adult↗

PubMed1994

The vascular concept of glaucoma.

The regulation of ocular perfusion is different for different parts of the eye. Observations on the retina can, therefore, not be extrapolated to the optic nerve head. Extraocular vessels, especially the short posterior ciliary arteries, might play a major role in regulation of ocular circulation, but additional regulation takes place in the eye itself. Dysregulation might be transient and, thus, not necessarily present and detectable at any one examination. Older patients with arteriosclerotic vessels may behave differently in this regard than do young, healthy animals. Not only the arterial but also the venous side of the circulation may be disturbed. Disk hemorrhages can not only be a sign of damage; they can also provoke ischemia. Besides hypoxia, diseased vessel walls might play a direct role in the pathogenesis of optic nerve head cupping. Finally, a relation between vascular dysregulation and aqueous-humor dynamics is conceivable.

Blood Flow Velocity↗

PubMed1994

Longterm visual field follow-up of glaucoma patients treated with beta-blockers.

In a prospective, randomized, double-masked study, 44 patients with primary open-angle glaucoma were treated either with 0.5% betaxolol or 0.5% timolol in both eyes twice daily. Twenty-nine patients could be followed up for 48 months. Seventeen of these patients were treated with betaxolol and 12 with timolol. Each examination included visual field measurements with an Octopus automated perimeter 201 (Program G1), intraocular pressure measurement, funduscopy, as well as pulse and arterial blood pressure measurements. Both drugs lowered in the intraocular pressure. This reduction was slightly but not statistically significantly higher in the timolol-treated group. However, the visual fields improved more in the betaxolol group. Patients treated with betaxolol had significantly smaller averaged mean defects (p < 0.05) and higher averaged mean sensitivities (p < 0.05, Wilcoxon rank score text) than did timolol-treated patients at months 3, 6, 12, and 18. Thereafter, the difference between the two groups was not statistically significant in this relatively small sample size. For betaxolol patients the cumulative area-under-the-curve analysis for the worse eye yielded significantly larger mean sensitivities beyond month 12 (exception: month 30; p < 0.05) and significantly smaller mean defects beyond month 6 (p < 0.05).

Aged↗

PubMed1994

[Experiences with mitomycin C].

BACKGROUND: Recently, encouraging results with the use of Mitomycin C in trabeculectomy have been reported. PATIENTS: We used Mitomycin C (0.028%) during trabeculectomy in 72 eyes of 68 patients. Forty-one eyes have already been controlled during 6 months and 19 eyes during 9 months after the surgery. RESULTS: The mean intraocular pressure after 6 and 9 months was respectively 13 +/- 8 mm Hg and 13 +/- 10 mm Hg. The difference between these results and the preoperative values (27 +/- 9 mm Hg) were statistically significant after 6 and 9 months (p < 0.001). Despite frequent choroidal detachments (20 eyes), the visual acuity recovered during the follow-up to the preoperative values. CONCLUSIONS: In patients with uncertain prognosis for the intraocular pressure after trabeculectomy, the intraoperative application of Mitomycin C seems to improve considerably the operative success rate.

Adult↗

PubMed1994

High-resolution perimetry of the central visual field.

The Octopus Program M1 was designed for the detection/follow-up of central or paracentral visual field defects in patients with neurological disorders or with macular or perimacular diseases. Within the central 25 degrees visual field, 59 test locations provide a resolution of < or = 1.4 degrees. The differential light sensitivity is measured with 'Octopus normal strategy', i.e. a 4/2/1 staircase procedure. The Program M2X has 81 test locations in the central 10 degrees, giving even higher resolution (< or = 0.7 degrees) of the central visual field. Both programs have 2 phases, the second being a re-test. Program M2X's phases are divided into 4 stages and allow interruption anytime.

Adult↗

PubMed1994

Comparison of the severity of normal-tension glaucoma in men and women.

To determine whether damage in normal-tension glaucoma is more pronounced in men or in women, we analyzed visual-field damage, intraocular pressure, age, frequency of acral vasospastic reaction on local cooling, and frequency of headache in 28 consecutive patients with newly diagnosed normal-tension glaucoma. The difference between genders with regard to mean visual-field defect was significant (9.4 +/- 1.3 dB in men and 6.7 +/- 1.0 dB in women; p = 0.034). This difference could not be explained by other variables. Because the population tested was relatively young, this study suggests normal-tension glaucoma to be more severe in men, in an earlier stage of the condition.

Female↗

PubMed1994

Optic disc cupping in arteritic anterior ischemic optic neuropathy.

Patients with anterior ischemic optic neuropathy due to giant cell arteritis are thought to develop optic disc cupping, resembling that seen in glaucomatous eyes, while such cupping does not seem to occur in nonarteritic anterior ischemic optic neuropathy. However, this remains controversial. We describe a patient with arteritic anterior ischemic optic neuropathy (the clinical diagnosis was confirmed with a biopsy from the temporal artery) who developed disc cupping within 4 months after acute episode. This patient never had elevated intraocular pressure, and prior to the acute event the optic nerve heads had had a normal appearance with a physiologic cup.

Aged↗

PubMed1993

Systemic blood pressure in glaucoma patients.

Blood pressure was monitored for 24 h in 32 control patients, 38 open-angle glaucoma patients referred because of decompensated IOP despite maximum treatment, 40 patients with open-angle glaucoma referred because of progressive damage despite controlled IOP, and 39 normal-tension glaucoma patients. In the control group a physiological drop in blood pressure during the night was observed. The patients referred with uncontrolled IOP had blood pressure very similar to that of the control group during both day and night. However, the open-angle glaucoma patients with progression despite well-controlled IOP and also the patients with normal-tension glaucoma had markedly, and statistically significantly, lower systolic blood pressure during both day and night. The difference in diastolic blood pressure was smaller. Thus, blood pressure should be considered in diagnosis.

Aged↗

PubMed1993

Correlation of spatial contrast sensitivity and visual fields in glaucoma.

Perimetry is the standard examination in glaucoma, whereas contrast sensitivity is often proposed as a complementary test. This study investigates the extent to which the outcomes of the two tests correlate. One eye each of 44 glaucoma patients and 16 glaucoma suspects was tested with the Haag-Streit Visometer and the Octopus 201 perimeter (program G1). Contrast sensitivities correlated highest with the center of the visual field (Spearman's rho = 0.76; P < 0.001) and slightly less with the mean sensitivity of the entire visual field (rho = 0.63; P < 0.001). Mean contrast sensitivity correlated weakly with the square root of corrected loss variance (rho = -0.45; P < 0.001) and short-term fluctuation (rho = -0.34; P < 0.007). The two tests differed considerably only in very few patients. We recommend careful evaluation of the central area of glaucomatous visual fields whenever contrast sensitivity testing is not available.

Contrast Sensitivity↗

PubMed1993

Swivel arm perimeter for visual field testing in different body positions.

To investigate the influence of body position on visual field results, a 'swivel arm perimeter' was built, based on a modified Octopus 1-2-3. Here, the measuring unit was detected from the control unit and mounted on a swivel arm, allowing its movement in all directions. The first results obtained with this device have indicated that its development was worthwhile.

Humans↗

PubMed1993

Do beta-blockers cause vasospasm?

The action of beta-blockers on papillary blood flow is quite controversial. Because there is a known relationship between digital and ocular vasospasm, we measured digital blood flow by laser-Doppler methods as a peripheral index of ocular vasospastic disorders. Thus, the effects of cardioselective (betaxolol) and noncardioselective (timolol) beta-blockers on peripheral blood flow in healthy volunteers were evaluated. Neither beta-blocker lowered peripheral blood flow; for betaxolol, there was even a significant increase compared to no medication. No significant differences between betaxolol and timolol were seen.

Adult↗