[Neuroprotection in glaucoma. What is the current status?].
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Biomedical subjects
Publications and source records attributed to M Gekkieva.
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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.
PURPOSE: To evaluate the relationship between ocular perfusion pressure and color Doppler measurements in patients with glaucoma. MATERIALS AND METHODS: Twenty patients with primary open-angle glaucoma with visual field deterioration in spite of an intraocular pressure lowered below 21 mm Hg, 20 age-matched patients with glaucoma with stable visual fields, and 20 age-matched healthy controls were recruited. After a 20-minute rest in a supine position, intraocular pressure and color Doppler measurements parameters of the ophthalmic artery and the central retinal artery were obtained. Correlations between mean ocular perfusion pressure and color Doppler measurements parameters were determined. RESULTS: Patients with glaucoma showed a higher intraocular pressure (P <.0008) and a lower mean ocular perfusion pressure (P <.0045) compared with healthy subjects. Patients with deteriorating glaucoma showed a lower mean blood pressure (P =.033) and a lower end diastolic velocity in the central retinal artery (P =.0093) compared with normals. Mean ocular perfusion pressure correlated positively with end diastolic velocity in the ophthalmic artery (R = 0.66, P =.002) and central retinal artery (R = 0.74, P <.0001) and negatively with resistivity index in the ophthalmic artery (R = -0.70, P =.001) and central retinal artery (R = -0.62, P =.003) in patients with deteriorating glaucoma. Such correlations did not occur in patients with glaucoma with stable visual fields or in normal subjects. The correlations were statistically significantly different between the study groups (parallelism of regression lines in an analysis of covariance model) for end diastolic velocity (P =.001) and resistivity index (P =.0001) in the ophthalmic artery, as well as for end diastolic velocity (P =.0009) and resistivity index (P =. 001) in the central retinal artery. CONCLUSIONS: The present findings suggest that alterations in ocular blood flow regulation may contribute to the progression in glaucomatous damage.
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.
PURPOSE: To assess sex difference and parameters possibly accounting for such a difference in healthy subjects evaluated by means of the Langham Ocular Blood Flow (OBF) System. METHODS: Pulse amplitude of intraocular pressure (IOP) and pulsatile ocular blood flow (POBF) as measured with the Langham OBF System were assessed in 86 healthy men and 69 healthy women. RESULTS: Compared to men, women showed higher POBF (mean +/- SD: 722.6 +/- 152.8 versus 647.8 +/- 164.9 microL/min; P =.0056) and pulse amplitude (mean +/- SD: 2.3 +/- 0.7 versus 2.0 +/- 0.6 mm Hg; P =.0043) values. Sex difference was still significant after correcting for age, refraction, blood pressure, IOP, and pulse rate. Pulse amplitude correlated negatively with pulse rate, and POBF correlated negatively with IOP. Women had higher readings in pulse amplitude and POBF, even after correcting for age, refraction, IOP, blood pressure, and pulse rate. CONCLUSIONS: While using the Langham OBF System, one needs to be aware of sex difference that is independent of other hemodynamic parameters. How the observed difference in POBF is related to ocular blood flow, and how it might influence the preponderance of various ocular diseases in men or women remains to be clarified.