[Vascular risk factors in glaucoma].
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Eye↗
Biomedical subjects
J Flammer
Publications and source records attributed to J Flammer.
Spontaneous calcium-independent nitric oxide synthase activity in porcine ciliary processes.
In the cornea, iris, retina, and ciliary processes of porcine eyes the nitric oxide synthase (NOS) activity was assayed by measuring the transformation of L-[U-14C]-arginine into L-[U-14C]-citrulline: (1) in the absence or presence of the calcium-chelator, ethylene glycol tetra acetic acid (EGTA), and (2) in the presence of EGTA and the false precursor of L-arginine, NG-nitro-L-arginine methyl ester (L-NAME). In the retina and the iris a high calcium-dependent NOS activity was present, while in the cornea the activity was relatively low. In these three tissues no significant calcium-independent NOS activity was detected. In contrast, a marked calcium-independent NOS activity, but no calcium-dependent NOS activity, was found in the ciliary processes. The presence of a spontaneous calcium-independent NOS activity in the ciliary processes suggests that nitric oxide (NO) production is highly regulated in this tissue.
Animals↗
Silent myocardial ischemia in glaucoma and cataract patients.
BACKGROUND: Glaucoma and cataract are multifactorial diseases. They have been described to be associated with cardiovascular risk factors. METHODS: Twenty-four-hour ECG monitoring was done in 22 normal-tension glaucoma patients, 27 open-angle glaucoma patients, 25 cataract patients, and 20 normal controls. The frequency of silent myocardial ischemia (SMI) as well as that of ventricular extrasystoles (VES) was evaluated. RESULTS: At least one episode of significant asymptomatic ST-T segment depression occurred in 45% of the normal-tension glaucomas, in 25.9% of open-angle glaucomas, in 12% of cataract patients, and in 5% of normal controls. The frequency of VES was not significantly different among the groups. CONCLUSIONS: Glaucoma, especially normal-tension glaucoma, is significantly associated with the occurrence of episodic asymptomatic myocardial ischemias. Cataract patients, however, had only a slightly, statistically not significantly increased frequency of both SMI and VES compared with normals.
Aged↗
The frequency distribution of blood-flow velocities in the extraocular vessels.
PURPOSE: The study was carried out in order to assess the distribution of normal values of the blood-flow velocity in the extraocular vessels. METHODS: In 240 healthy visitors to a public fair, blood-flow characteristics in the extraocular vessels were measured, and the resistivity index was calculated. Blood-flow velocity was measured with a color Doppler imaging device, using a 7.5-mHz linear-array transducer. Peak-systolic and end-diastolic blood-flow velocities in the arteries were measured, and the resistivity index was calculated. In the central retinal vein the minimal and maximal blood-flow velocities were measured. The statistical analysis of the 14 measured and calculated variables included descriptive statistics, frequency distribution, and quantile plots. RESULTS: The quantile plots of the cumulative frequency showed that none of these 14 variables are normally distributed. Also, no normal distribution could be achieved by adjustment of the data by age. CONCLUSIONS: The blood-flow velocities in the extraocular vessels measured are not distributed normally. Therefore, nonparametric tests are to be used for statistical analysis if the sample size is small. The estimation of tolerance intervals has to be based on distribution-free assumptions.
Adolescent↗
Choroidal capillary and venous congestion in central serous chorioretinopathy.
PURPOSE: Abnormalities in choroidal perfusion have been hypothesized to be causative factors in central serous chorioretinopathy. This prospective study was performed to evaluate changes in the choroidal circulation in cases of central serous chorioretinopathy. METHODS: In 32 consecutive patients with acute or chronic recurrent central serous chorioretinopathy, complete clinical ophthalmologic examinations, fluorescein angiography, and indocyanine green angiography with a scanning laser ophthalmoscope and a digital imaging system were performed. RESULTS: All patients with acute and chronic recurrent central serous chorioretinopathy demonstrated a localized delay in arterial filling followed by choroidal hyperperfusion in the area of the damaged retinal pigment epithelium, frequently associated with dilated capillaries and dilated draining venules in one or more choroidal lobules. These changes corresponded to areas with pigment epithelial detachment or focal leakage from the retinal pigment epithelium found in fluorescein angiography. Furthermore, in some patients, localized choroidal ischemia could be observed in additional areas throughout the central fundus in both diseased eyes and normal fellow eyes. CONCLUSIONS: Delayed arterial filling followed by capillary and venous hyperemia, angiographically appearing as capillary and venous congestion, can be observed frequently in eyes with central serous chorioretinopathy. The results suggested that capillary or venous congestion after ischemia in one or more choroidal lobules might be the reason for the choroidal hyperpermeability associated with central serous chorioretinopathy.
Acute Disease↗
Blood-flow velocities in the extraocular vessels in normal volunteers.
PURPOSE: To determine normal values of blood-flow velocities in extraocular vessels. METHODS: In one eye each in 189 healthy adult volunteers, blood-flow velocities in the ophthalmic artery (OA), central retinal artery (CRA), central retinal vein (CRV), short lateral posterior ciliary artery (LPCA), and short medial posterior ciliary artery (MPCA) were measured by color Doppler imaging. In the arteries, peak systolic velocity (PSV), end diastolic velocity (EDV), and resistivity index (RI) were calculated. In the CRV, maximal and minimal blood-flow velocities were measured. Influence of age, gender, blood pressure, and heart rate on blood-flow velocities and the resistivity index were analyzed. RESULTS: Mean outcomes +/- S.D. cm/sec were as follows: in the OA, PSV was 39.2 +/- 5.3, EDV was 9.1 +/- 2.5, and RI was 0.77 +/- 0.05. In the CRA, PSV was 11.0 +/- 1.8, EDV was 3.3 +/- 0.9, and RI was 0.71 +/- 0.05. In the short LPCA, PSV was 11.2 +/- 1.7, EDV was 3.7 +/- 1.0, and RI was 0.68 +/- 0.06. In the short MPCA, PSV was 11.2 +/- 11.7, EDV was 3.6 +/- 0.9, and RI was 0.68 +/- 0.05. In the CRV, mean maximal velocity was 4.5 +/- 0.9, and mean minimal velocity was 3.3 +/- 0.7. Age, gender, systolic blood pressure, diastolic blood pressure, and heart rate had no consistent statistically significant influence on the measured and calculated variables. CONCLUSION: Normal values for blood-flow velocities in the extraocular vessels serve as a basis in deciding whether a measured value of a patient is normal or abnormal.
Adolescent↗
[Central vein thrombosis in younger patients].
BACKGROUND: Vein thromboses are not seldom, even in young patients. The pathogenesis of such perfusion disorders is poorly understood-accordingly, it is difficult to choose therapy specific to the causality and appropriate prophylaxis against recurrence. PATIENTS AND METHODS: In a retrospective study we analyzed the clinical findings of seven patients under 45 years of age who suffered a retinal vein occlusion in the past two years. RESULTS: Anatomical changes of the vessels in carotis and ophthalmica regions were not found, as was the case in hemostasis and fibrinolysis, as well. However, all patients reported stress problems in family and occupation. Migraine was often mentioned in the anamnesis. Coldness of the extremities and perfusion disorders in the nailfold capillaries examined under capillary microscopy indicated increased vasospasm. CONCLUSIONS: Vein thromboses are affections of both the arterial and venous circulation. We hypothesize that dysregulation of vascular tone plays an essential role in the genesis of retinal vein thromboses. Increased vasospasm and the incapacity to reactively dilate are potential mechanisms for such perfusion disorders. When counseling patients and applying medical therapy, such a possible pathogenesis should be taken into consideration.
Adult↗
[Circulatory disorders of the choroid in patients with central serious chorioretinopathy].
BACKGROUND: Advanced methods for indocyanine green (ICG) video-fluorescence angiography provide improved evaluation of choroidal blood flow disturbances in patients with central serous chorioretinopathy (CSC). MATERIAL AND METHOD: Fluorescein ICG video-fluorescence angiography using a laser scanning ophthalmoscope and digital image processing were performed in patients with acute or chronic recurrent CSC. RESULTS: In all eyes examined delayed arterial filling followed by capillary and/or venous congestion were found in the areas of retinal pigmentepithelial detachment or leakage. Furthermore, additional ischemic choroidal capillary lobuli could be observed throughout the fundus of diseased eyes and "normal" fellow eyes. CONCLUSIONS: Our results suggest that symptomatic changes in CSC, like RPEdetachment or leakage from the outer blood-retinal barrier, may be caused by capillary and venous congestion, possibly due to stress-related arterial hypoperfusion.
Acute Disease↗
Effect of dipyridamole on vascular responses of porcine ciliary arteries.
This study investigated the effects of dipyridamole in isolated porcine ciliary arteries (diameter 200-250 microns). Isolated porcine ciliary arteries were suspended in myograph chambers filled with modified Krebs-Ringer solution (37 degrees C; 95% O2/5% CO2) for isometric tension recording. Dipyridamole induced concentration-dependent relaxations of porcine ciliary arteries with endothelium precontracted with thromboxane analogue U-46619 (10(-6)M), KCl (50 mM), or endothelin-1 (10(-8)M). Removal of the endothelium of the ciliary vessels and preincubation of the arteries with L-NAME (10(-5)M), or indomethacin (10(-5)M), or the combination of the two drugs significantly reduced the relaxation to dipyridamole (p = 0.002-0.03). Similar vascular responses could be observed in a time-dependent analysis of the effect of a single concentration dipyridamole (10(-4)M). The stimulator of cAMP forskolin also caused relaxations. Endothelin-1 (10(-12)-10(-7)M) and U-46619 (10(-10)-10(-6)M) induced potent contractions of porcine ciliary arteries. Preincubation with dipyridamole (10(-5)M) reduced contractions to endothelin-1 as compared to control (p < 0.004), while contractions to U-46619 were only slightly affected under these conditions (n.s.). These findings demonstrate that dipyridamole is a vasodilator in porcine ciliary arteries. Endothelial nitric oxide and prostacyclin contribute importantly to the effects of dipyridamole. Further studies are required to show whether these properties of dipyridamole may also occur in vivo and offer clinical use in patients with ocular vasospasms and other ophthalmic vascular dysfunctions.
15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
[Vision disorders and their causes].
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Humans↗
Regression of rubeosis iridis after trabeculectomy combined with mitomycin-C.
The authors report two cases in which severe rubeosis iridis regressed after trabeculectomy with intraoperative application of mitomycin-C. Several days after the operation, the vessels were no longer perfused. Only white, empty, "ghost" vessels were visible. This phenomenon was observed in one case with well-controlled intraocular pressure (IOP) after surgery, as well as in a case in which IOP rose again to high preoperative values. The authors conclude that the regression of the rubeosis may be caused by a local, intraocular pharmacologic side effect of mitomycin-C, not by the drop in IOP alone.
Aged↗
[Perimetry with normal Octopus technique and Weber 'dynamic' technique. Initial results with reference to reproducibility of measurements in glaucoma patients].
UNLABELLED: There is ample reason to strive for a shorter test without losing solid and reproducible information on the function of the eye. The purpose of this study was to compare the standard Octopus strategy with the 'dynamic strategy' of Weber in terms of time requirement and reproducibility of results, i.e., short-term as well as long-term fluctuations in glaucoma. MATERIALS AND METHODS: On an Octopus 1-2-3 automated perimeter, 23 experienced glaucoma patients with predominantly local loss completed three test sessions, each consisting of a short training test followed by six visual fields, i.e., the first 'stage' (16 test locations) of program GIX, beginning at random with one strategy, then alternating the strategies. RESULTS: The deviation from normal values of the 1104 test locations obtained with the standard and the dynamic strategy (mean +/- SD) was 5.2 +/- 7.5 dB and 4.6 +/- 7.3 dB (P < 0.02), respectively. The short-term fluctuation (given as variance) with the standard and the dynamic strategy averaged 8.3 +/- 5.9 dB2 and 10.2 +/- 5.8 dB2 (p < 0.02), respectively. The long-term fluctuation, i.e., 'test-to-test' variation (given as variance), with the standard and the dynamic strategy was 6.4 +/- 16.5 dB2 and 7.89 +/- 19.2 dB2 (P < 0.22), respectively. The total long-term fluctuation of the index mean defect, MD, averaged 1.8 +/- 2.7 dB2 and 1.3 +/- 1.7 dB2 (P = 0.69), respectively, with the standard and the dynamic strategy. The number or stimuli required with the standard and the dynamic strategy averaged 5.6 +/- 1.4 and 3.0 +/- 1.0 (P < 0.001), respectively. CONCLUSIONS: The dynamic strategy required 43% fewer stimuli and presented 23% (significantly) higher short-term fluctuation, but long-term fluctuations were similar for both strategies. The two strategies were comparable regarding the respective reproducibility of the results. However, further studies may investigate the sensitivity and the specificity of either strategy to distinguish disease from normal, or, change during a follow-up of a disease, and, may elucidate whether the observed differences between the two strategies are due to the modified step size, or, to the single (versus double) crossing of the threshold.
Adult↗
Reproducibility of color Doppler imaging in orbital vessels.
The purpose of this study was to evaluate the short-term reproducibility, the long-term reproducibility, and the reproducibility of the measurements made between two different examiners of blood-flow velocity in extraocular vessels using color Doppler imaging (CDI). In a group of 10 healthy volunteers, measurements of the peak-systolic velocity (PSV), end-diastolic velocity (EDV), and resistivity index (RI) in the ophthalmic artery and the central retinal artery as well as one lateral and one medial short posterior ciliary artery were performed. The best intraindividual reproducibility, expressed as the relative error, was found for the PSV and RI measured in the ophthalmic artery (OA; PSV 5.9%, RI 3.1%) and the central retinal artery (CRA; PSV 7.7%, RI 4.7%). The PSV and RI determined in the posterior ciliary arteries were less reproducible but as much so as the EDV measured in the OA (11.8%) and CRA (19.9%). No systematic trend could be found between the first and second measurements. However, the long-term fluctuation was considerable high. Measurements of PSVs showed good concurrence between the two observers in all four vessels measured. The EDVs and RIs differed statistically significantly between the two observers. This difference was most pronounced in the posterior ciliary arteries.
Adult↗
Intraocular pressure decrease after local ocular cooling is underestimated by applanation tonometry.
BACKGROUND: The effects of intense systemic or local cooling on aqueous humor dynamics in animals are an increased total outflow facility and a decreased aqueous flow. Few studies suggest that only vasoconstriction of arteriolar segments of the episcleral vasculature may be the cause for a decrease in intraocular pressure after local cooling in humans. Because corneal changes may have influenced such studies, the effect of local cooling was assessed in normal subjects. METHODS: Intraocular pressure and corneal thickness were measured in 18 healthy human subjects before and after exposure of the right eye to both, an air stream at 20 degrees C, and an air stream at 0 degrees C. RESULTS: No significant changes in IOP or corneal thickness occurred under 20 degrees C conditions. After local cooling, the mean corneal thickness increased from 0.52 +/- 0.01 mm to 0.57 +/- 0.02 mm (p < 0.001). Mean intraocular pressure decreased from 13.8 +/- 2.9 mmHg to 12.9 +/- 3.1 mmHg (p < 0.026). The observed decrease in IOP correlated significantly but negatively (R = -0.53; p = 0.024) with the increase in corneal thickness, indicating that the cooling effect on IOP may be rather underestimated. CONCLUSION: The eye is very sensitive to local cooling effects, which may, however, partially be masked by changes in corneal thickness.
Adult↗
Endothelin-1 plasma levels in normal-tension glaucoma: abnormal response to postural changes.
BACKGROUND: Endothelin-1 (ET-1) is a potent vasoconstrictor peptide produced by vascular endothelial cells. ET-1 may have a role in the pathogenesis of various vascular diseases. There are reports in the literature that ET-1 plasma levels are raised in normal-tension glaucoma (NTG) patients. METHODS: ET-1 concentration, plasma renin activity, and 24-h blood pressure were measured in 21 high-tension glaucoma (HTG) patients, 19 NTG patients, and 20 non-glaucomatous controls in supine and upright positions. RESULTS: ET-1 plasma levels tended to be higher in NTG patients (3.2 +/- 2.2 pg/ml) than in HTG patients (2.2 +/- 0.6 pg/ml) and controls (2.6 +/- 0.7 pg/ml). The differences, however, were not statistically significant. The individual scatter was significantly greater in the NTG group, indicating that our NTG patients are a heterogeneous population. The physiological increase in ET-1 plasma level after changing from the supine to the upright position was absent in NTG patients. Plasma renin activities tended to be lower in NTG patients (1.2 +/- 1.2 ng/ml/h) than in HTG patients (1.3 +/- 0.8 ng/ml/h) and controls (2.0 +/- 1.7 ng/ml/h). This may explain why NTG patients had relatively low blood pressure despite high ET-1 levels. CONCLUSIONS: Our data support the hypothesis that vascular dysfunction may be involved in the pathogenesis of optic nerve damage in normal-tension glaucoma.
Blood Pressure↗
Effects of calcium channel blockers on the response to endothelin-1, bradykinin and sodium nitroprusside in porcine ciliary arteries.
Calcium channel blockers are increasingly used in ophthalmology, for instance in patients with visual field defects caused by vasospasm. Endothelin is a new vasoactive peptide which also has been implicated in hypoperfusion of the ophthalmic circulation. This study investigated the effects of the calcium channel blockers on the response to endothelin-1, bradykinin and sodium nitroprusside in isolated porcine ciliary arteries (diameter 200-250 microns). Isolated porcine ciliary arteries were suspended in myograph systems filled with modified Krebs-Ringer solution (37 degrees C; 95% O2/5% CO2) for isometric tension recording. Endothelin-1 (10(-12) -10(-7) M) induced potent concentration-dependent contractions of porcine ciliary arteries (PD50 = 8.3 +/- 0.1; n = 7). Lacidipine (10(-5) -10(-7) M) and nifedipine (10(-5) M) significantly reduced the contractions and decreased the sensitivity to endothelin-1 as compared to control (P < 0.03). On the other hand, endothelium-dependent relaxations to bradykinin (10(-10) -10(-6) M) and endothelium-independent relaxations to sodium nitroprusside (10(-10) -10(-4) M) remained unaffected by the calcium channel blocker. These findings demonstrate that in porcine ciliary arteries, the calcium channel blockers selectively inhibit endothelin-1-induced contractions, while leaving endothelium-dependent and endothelium-independent relaxations unaffected. This property of calcium channel blockers may contribute to the clinical efficacy of this class of drugs in patients with ocular vasospasms.
Animals↗
The novel dopamine D-1 antagonist and D-2 agonist, SDZ GLC-756, lowers intraocular pressure in healthy human volunteers and in patients with glaucoma.
PURPOSE: To investigate the intraocular pressure (IOP)-reducing effect and side effects of SDZ GLC-756, a novel dopamine D-1 antagonist and D-2 agonist, in control subjects and patients with open-angle glaucoma or ocular hypertension. METHODS: A single-application, randomized, placebo-controlled, double-masked study was performed. SDZ GLC-756 eye drops at a concentration of 0.01% (n = 6) or 0.1% (n = 6) were administered to one eye in control subjects, vehicle alone (control) to the contralateral eye. In glaucoma patients the trial was designed as a crossover study administering SDZ GLC-756 (0.1%) eye drops and vehicle alone (control) to one eye in 12 patients with open-angle glaucoma or ocular hypertension. RESULTS: In control subjects, IOP decreased significantly by 2.0 +/- 0.4 mmHg (P < 0.01) after treatment with 0.01% SDZ GLC-756 and by 4.7 +/- 0.5 mmHg (P < 0.001) after treatment with 0.1% SDZ GLC-756. In the glaucoma group, IOP decreased by 6.8 +/- 0.6 mmHg (P < 0.001) (range, 4-11 mmHg). In both groups, treatment with 0.1% eye drops resulted in a significant IOP-lowering effect for 6 hours, and for 3 hours with treatment with 0.01% eye drops. A significant IOP-lowering effect (P < 0.05) also was found in the contralateral eye. Except for slight conjunctival hyperemia lasting up to 30 minutes after drug application, no ocular or systemic side effects were observed. CONCLUSION: SDZ GLC-756 reduced IOP significantly for approximately 6 hours. However, due to the study design with repeated IOP measurements before drug administration, the clinical efficacy of the preparation used remains unclear. The only systemic or local side effect observed was slight conjunctival hyperemia. The simultaneous D-1 antagonistic and D-2 agonistic properties of SDZ GLC-756 may provide a new pharmacologic approach to treating glaucoma and ocular hypertension, which deserves further investigation.
Adolescent↗
The influence of magnesium on visual field and peripheral vasospasm in glaucoma.
Previous studies indicated calcium channel blockers to be of some help for normal-tension glaucoma patients. The present study evaluates the effect of magnesium, a 'physiological calcium blocker', in 10 glaucoma patients (6 with primary open-angle glaucoma, 4 with normal-tension glaucoma). All patients had a digital cold-induced vasospasm. Magnesium (121.5 mg) was administered twice a day for a month. After 4 weeks of treatment, the visual fields tended to improve. All three video-nailfold-capillaroscopic parameters [blood cell velocity (in mm/s) before and after cooling, cold-induced blood flow cessation (in seconds) as well as the number of capillaries per microscopic field which showed such a blood flow cessation] as well as digital temperature improved significantly. Systemic blood pressure and pulse rate remained stable. In conclusion, magnesium improves the peripheral circulation and seems to have a beneficial effect on the visual field in glaucoma patients with vasospasm.
Blood Flow Velocity↗