Biomedical subjects

P Lübeck

Publications and source records attributed to P Lübeck.

3 recordsLinked to original sources

PubMed2001

Effect of timolol on anterior optic nerve blood flow in patients with primary open-angle glaucoma as assessed by the Heidelberg retina flowmeter.

PURPOSE: To evaluate the effect of 0.5% timolol maleate on the capillary circulation of the anterior optic nerve head in patients with primary open-angle glaucoma and to compare the results with those obtained in a healthy control group. PATIENTS AND METHODS: Twelve patients with nonprogressive glaucoma and 12 age- and sex-matched healthy volunteers were included in this prospective study. Optic nerve head perfusion was examined by the Heidelberg Retina Flowmeter (HRF) in both groups. A 3-week washout period preceded the baseline measurement in the glaucoma group, and ONH blood flow was assessed again after 3 weeks of bilateral topical timolol treatment and 2 hours after timolol application. RESULTS: Intraocular pressure decreased significantly with timolol (P < 0.001). The HRF flow values for patients with glaucoma were comparable to those for a control group at baseline (P = 0.25), 3 weeks after timolol therapy (P = 0.09), and 2 hours after timolol instillation (P = 0.15). The glaucoma group showed no statistically significant change in the HRF parameter flow as compared with baseline, either after 3 weeks of timolol treatment or 2 hours after timolol instillation (P = 0.40). The heart rate and arterial systolic and diastolic blood pressure values showed no alteration after timolol therapy. CONCLUSIONS: Patients with nonprogressive glaucoma seem not to have an altered optic nerve blood flow as assessed by the HRF, and timolol treatment does not seem to alter the latter blood flow parameter in such patients.

Adrenergic beta-Antagonists↗

PubMed2000

Interocular differences in optic disc topographic parameters in normal subjects.

PURPOSE: To test the interocular differences in optic disc topography in normal subjects by means of confocal scanning laser ophthalmoscopy. METHODS: Topographic measurements of the optic disc were evaluated by means of confocal scanning laser ophthalmoscopy (Heidelberg Retina Tomograph) in 314 eyes of 157 healthy volunteers. The examination was started randomly either with the right eye or the left eye. Differences between right and left eyes in disc area, cup area, cup volume, cup/disc area ratio, rim area, rim volume, maximum cup depth, cup shape measure, retinal nerve fiber layer thickness, and retinal nerve fiber cross section area for 360 degrees and for the temporal and nasal regions of the optic nerve head were evaluated by means of Student t-test. The same parameters were assessed in a subgroup of 80 elderly (age> 50 years) healthy subjects. Holm's sequentially rejective method was used for significance correction of multiple comparisons. RESULTS: Significant interocular differences in the average retinal nerve fiber layer thickness (p = 0.0010) and retinal nerve fiber layer cross section area (p = 0.0036) were found, with the right eye showing, on the average, lower values. The left eye showed a larger retinal nerve fiber layer thickness in 94 subjects (59.87%) and a larger retinal nerve fiber cross section area in 101 subjects (64. 33%). In the temporal optic disc area there were no statistically significant differences in topometric data (p> 0.05). In the nasal area, significant interocular differences in the retinal nerve fiber layer thickness (p = 0.0002) and retinal nerve fiber layer cross section area (p = 0.0003) were found. Similar results were found when the group of subjects older than 50 years was considered. CONCLUSIONS: This study demonstrates systematic interocular differences in optic disc topometric data. Such a finding, be it due to methodological or biological reasons, should be taken in consideration in clinical trials.

Adolescent↗

PubMed1999

Is vascular regulation in the central retinal artery altered in persons with vasospasm?

OBJECTIVE: To assess the relation between ocular perfusion pressure and blood flow velocity in the central retinal artery in patients with acral vasospasm. SUBJECTS AND METHODS: Eighteen otherwise healthy subjects with acral vascular dysregulation, as demonstrated by nail-fold capillaroscopy, and 18 age- and sex-matched healthy volunteers without vasospasm were recruited. After subjects had rested for 20 minutes in a supine position, intraocular pressure and blood flow velocity in the central retinal artery were determined by applanation tonometry and color Doppler imaging, respectively. The peak systolic velocity, end-diastolic velocity, and resistivity index were assessed. Correlations between the mean ocular perfusion pressure (2/3 x [2/3 x diastolic blood pressure + 1/3 x systolic blood pressure] - intraocular pressure) and blood flow velocities in the central retinal artery were determined by the Pearson linear correlation factor. The Student t test was used to evaluate differences between controls and subjects with vasospasm. RESULTS: The mean +/- SD ocular perfusion pressure was 42.0 +/- 7.4 mm Hg in the group with vasospasm and 47.1 +/- 6.5 mm Hg in the control group (P= .04). In the subjects with vasospasm, the peak systolic and end-diastolic velocities and the resistivity index of the central retinal artery correlated significantly with the mean ocular perfusion pressure (R = 0.49, P = .04 P = .01; and R = -0.67, P = .002, respectively). Such correlations were not found in the control group. CONCLUSIONS: An altered blood flow regulation is suggested in the ocular circulation of patients with acral vasospasm.

Adult↗