Daniela Stümpfig

Blood-flow Velocities of the Extraocular Vessels in Patients With High-tension and Normal-tension Primary Open-angle Glaucoma

PURPOSE To evaluate blood-flow parameters in three different groups of patients with primary open-angle glaucoma. METHODS Hemodynamic parameters in the ophthalmic artery, central retinal artery, central retinal vein, and lateral and medial short posterior ciliary arteries were evaluated by color Doppler imaging in 237 patients with primary open-angle glaucoma and 124 age-matched normal control subjects. Group A consisted of 56 patients with primary open-angle glaucoma with treated intraocular pressure higher than 20 mm Hg; group B, of 103 patients with primary open-angle glaucoma with progression of glaucomatous damage despite intraocular pressure of 21 mm Hg or less; and group C, of 78 patients with normal-tension glaucoma. RESULTS All patients showed a significant decrease in end-diastolic velocities (P < .01) and a significant increase in resistivity index (P < .05) in all arteries measured. Peak-systolic velocities were normal in the ophthalmic artery in all three groups. In the central retinal artery and the short posterior ciliary arteries, however, patients in groups B and C had significantly reduced peak-systolic velocity (P < .05) compared with normal control subjects. Peak-systolic velocity in group A did not differ significantly from that of normal control subjects. Maximal and minimal blood-flow velocities in the central retinal vein were significantly lower in groups B and C (P < .001) compared with normal control subjects. In group A, only minimal blood-flow velocity was significantly reduced (P < .05). CONCLUSIONS Hemodynamic parameters in the extraocular vessels are altered in patients with glaucoma. Reduced blood-flow velocities may be secondary as well as contributory to glaucomatous damage.

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.

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).

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).

SHORT-TERM EFFECT OF DIPYRIDAMOLE ON BLOOD FLOW VELOCITIES IN THE EXTRAOCULAR VESSELS

Dipyridamole is known to inhibit platelet aggregation and to induce vasodilatation. It has been shown that dipyridamole increases blood flow in various tissues in humans as well as in the eyes of animals. We studied the influence of dipyridamole in a prospective open trial in 23 patients with impaired ocular circulation due to different causes, based on experienced clinical judgement, such as anterior ischemic optic neuropathy, vasospastic syndrome, glaucoma, or central retinal vein occlusion. Blood flow velocities in the ophthalmic artery, central retinal artery and vein, one lateral and one medical posterior ciliary artery were measured using a Siemens Quantum 2000 color Doppler device. Blood flow velocities were measured before and under treatment. Dipyridamole increased blood flow velocities significantly in all vessels measured. Therefore, it seems promising to evaluate the effect of dipyridamole over a longer period in patients with impaired ocular blood flow.

An evaluation of the effect of unoprostone isopropyl 0.15% on ocular hemodynamics in normal-tension glaucoma patients

Abstract. Background: Because intraocular pressure-lowering agents should have a good safety profile with regard to ocular hemodynamics, the innocuousness of unoprostone isopropyl 0.15% with regard to ocular hemodynamics in vasospastic patients with normal-tension glaucoma was assessed in a pilot study. Methods: Corneal temperature as a parameter of ocular blood flow and choroidal and optic nerve blood flow as assessed by means of laser Doppler flowmetry techniques were evaluated in 12 vasospastic normal-tension glaucoma patients in a prospective, randomized, observer-masked, two-period crossover, placebo-controlled pilot trial. Results: Statistical analysis in 2×2 two-way analysis of variance models with two treatments (placebo and unoprostone isopropyl) and two assessments (baseline and after 1 week of treatment) as within-subject factors disclosed a lack of difference between eyes, between the treatment (placebo/unoprostone isopropyl) periods, and between baseline and after 1 week of treatment in corneal temperature, choroidal blood flow, and optic nerve blood flow. The differences between the results at baseline and after 1 week of treatment in these parameters were not significantly different between the placebo treatment period and the unoprostone isopropyl treatment period, and this was comparable in fellow eyes for all the parameters. Conclusion: Unoprostone isopropyl did not induce any alterations in ocular hemodynamics in this pilot study with vasospastic normal-tension glaucoma patients.

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, Students t test). These findings indicate that in some glaucoma patients the regulatory mechanisms for blood supply in the optic nerve head are insufficient.

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° C, and an air stream at 0° C. Results: No significant changes in IOP or corneal thickness occurred under 20° 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.

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.