Hypertension Primary Open-angle Glaucoma Research Articles

Ocular Pulse Amplitude in Patients with Asymmetric Primary Open-Angle Glaucoma

Aim: To evaluate ocular pulse amplitude (OPA) using the dynamic contour tonometer (DCT) in patients with asymmetric primary open-angle glaucoma (POAG) and asymmetric intra-ocular pressure (IOP).Methods: The participants consisted of 48 patients (96 eyes) with asymmetric POAG. Three measurements of IOP and OPA were taken using DCT. The diagnosis of asymmetry required a difference of glaucomatous visual field loss greater than 6 dB in the global index MD and a difference of 5 mmHg in IOP measured by Goldmann tonometry between the more affected and the contra-lateral eye. All participants underwent full ophthalmologic clinical assessment including ultrasonic pachymetry and biometric measurements. Exclusion criteria were corneal diseases or scars, topical or systemic glaucomatous medications, and previous ocular surgery.Results: No difference (p = 0.142) was found between the axial length measurements of the better eyes group (22.95 ± 0.91 mm) and worse eyes group (22.85 ± 0.97 mm). There was a statistically significant difference (p = 0.011) between the central corneal thickness values of the better eyes group (537.08 ± 29.54 μm) and worse eyes group (534.40 ± 29.87 μm). The OPA values of the better eyes group (3.32 ± 1.14 mmHg) were significantly lower (p = 0.001) than those obtained in the worse eyes group (3.83 ± 1.27 mmHg). When correcting the OPA readings by the IOP there was no statistical difference between groups (p = 0.996).Conclusion: Higher OPA values were found in eyes with higher IOP levels and advanced glaucoma’s lesions in asymmetric hypertensive POAG patients. However, after the OPA correction by the IOP levels there was no more statistical difference between eyes.

Color Doppler imaging and pattern visual evoked potential in normal tension glaucoma and hypertension glaucoma

To compare the differences in color Doppler imaging (CDI) and pattern visual evoked potential (P-VEP) examinations between normal tension glaucoma (NTG) and hypertension primary open angle glaucoma (HTG) patients, and investigate the relation between flow velocities measured by CDI and P-VEP examination in NTG and HTG patients. Sixty NTG patients, 66 HTG patients and 44 control subjects underwent CDI evaluation of the ophthalmic artery (OA), short posterior ciliary artery (SPCA) and central retinal arteries (CRA). The peak systolic velocities (PSV) and end-diastolic velocities (EDV) and resistive index (RI) of all retrobulbar vessels were measured. The latency and amplitude of P100 in P-VEP were recorded from the three groups. The differences of CDI and P-VEP parameters among NTG group, HTG group and control group were compared by one-way analysis of variance. The correlations between CDI parameters and visual field indices, P-VEP and visual field indices, P-VEP and CDI parameters in NTG and HTG patients were evaluated by Pearson's correlation analysis. NTG and HTG patients had the lower EDV and higher RI in the OA, CRA and SPCA comparing with that of control subjects. NTG and HTG patients also had lower PSV in OA and CRA comparing with that of control subjects. There was no significant difference in the blood flow velocities and RI of all retrobulbar vessels between NTG and HTG patients. The latency of P100 in VEP delayed and the amplitude of P100 decreased in the NTG and HTG patients comparing with that of the control group. There was no significant difference in the latency and amplitude of P100 between the NTG and HTG patients. The RI of OA and SPCA were negatively correlated with the mean deviation (MD) values in the NTG and HTG patients. The RI of OA was positively correlated with the PSD value in the NTG and HTG patients. The MD values in the NTG and HTG patients were negatively correlated with the latency time of P100. The RI of OA was positively correlated with the latency time of P100 in NTG and HTG patients. The RI of OA was negatively correlated with the amplitude of P100 in HTG patients. No significant difference was found in the parameters of CDI and P-VEP between NTG and HTG patients. The certain parameters of CDI were correlated with P-VEP parameters in NTG and HTG patients.

Transitions of multifocal electroretinography in patients with age-related macular degeneration after combination therapy with photodynamic therapy and intravitreal bevacizumab

To compare the differences in color Doppler imaging (CDI) and pattern visual evoked potential (P-VEP) examinations between normal tension glaucoma (NTG) and hypertension primary open angle glaucoma (HTG) patients, and investigate the relation between flow velocities measured by CDI and P-VEP examination in NTG and HTG patients. Sixty NTG patients, 66 HTG patients and 44 control subjects underwent CDI evaluation of the ophthalmic artery (OA), short posterior ciliary artery (SPCA) and central retinal arteries (CRA). The peak systolic velocities (PSV) and end-diastolic velocities (EDV) and resistive index (RI) of all retrobulbar vessels were measured. The latency and amplitude of P100 in P-VEP were recorded from the three groups. The differences of CDI and P-VEP parameters among NTG group, HTG group and control group were compared by one-way analysis of variance. The correlations between CDI parameters and visual field indices, P-VEP and visual field indices, P-VEP and CDI parameters in NTG and HTG patients were evaluated by Pearson's correlation analysis. NTG and HTG patients had the lower EDV and higher RI in the OA, CRA and SPCA comparing with that of control subjects. NTG and HTG patients also had lower PSV in OA and CRA comparing with that of control subjects. There was no significant difference in the blood flow velocities and RI of all retrobulbar vessels between NTG and HTG patients. The latency of P100 in VEP delayed and the amplitude of P100 decreased in the NTG and HTG patients comparing with that of the control group. There was no significant difference in the latency and amplitude of P100 between the NTG and HTG patients. The RI of OA and SPCA were negatively correlated with the mean deviation (MD) values in the NTG and HTG patients. The RI of OA was positively correlated with the PSD value in the NTG and HTG patients. The MD values in the NTG and HTG patients were negatively correlated with the latency time of P100. The RI of OA was positively correlated with the latency time of P100 in NTG and HTG patients. The RI of OA was negatively correlated with the amplitude of P100 in HTG patients. No significant difference was found in the parameters of CDI and P-VEP between NTG and HTG patients. The certain parameters of CDI were correlated with P-VEP parameters in NTG and HTG patients.

472 Inhibiteurs des canaux calciques dans l’hémodynamique oculaire du glaucome

To investigate Ca blockers effect on the ocular hemodynamic in glaucoma patients. Clinical, observational, prospective study on two groups of patients with primary open angle glaucoma (POAG): group A – 15 patients with hypertensive POAG and group B – 8 patients with normal tension POAG. Both groups of patients received oral therapy with nimodipinum (30mg × 3/zi) – a Ca blocker with preponderent vascular effect mainly in cerebral circulation. For each patient the intraocular pressure (IOP), the arterial pressure and the hemodynamic activity in the central artery of the retina by color Doppler imaging were measured at the begining of the study and after 3 weeks of treatment. Exclusion criteria was any associated ocular or general pathology. Both groups were homogeneous by age and sex. ocular hemodynamic: the peack sistolic velocity (PSV), the end diastolic velocity (EDV) and the resistivity index (RI) in the central artery of the retina show that at the begining of the study group B has the velocities values lower than group A. At 3 weeks post-treatment, we observe an amelioration of these values by statistically significativ increases of PSV and EDV and decrease of RI. We did not notice the alterations on IOP or hypo-arterial tensions episodes. In the plurifactorial etiopathology of the glaucoma, impaired ocular perfusion is an important coparticipant factor. We have to find out the easiest way to be efficient in this part of treatment. This study demonstrates that the involvement of ocular blood flow is an important factor in the pathogenesis of the glaucoma, the hemodynamic alterations being increased in the normal tension glaucoma. Action of nimodipinum on vasoconstriction and vasospasm as a potent cerebral vasoactive agent has to be studied.

Acetazolamide Influences Ocular Pulse Amplitude

To investigate the effect of systemic acetazolamide on ocular pulse amplitude (OPA) and on intraocular pressure (IOP). We determined OPA, IOP, mean arterial blood pressure and heart rate (HR) in 17 patients suffering from hypertensive primary open-angle glaucoma (htPOAG) and 22 healthy controls. Measurements were taken before and 2 h after oral intake of 500 mg of acetazolamide. Mean OPA decreased 20.24% (SEM 2.95%) from 2.76 mmHg (SEM 0.16 mmHg) to 2.14 mmHg (SEM 0.13 mmHg) 2 h after oral administration of 500-mg acetazolamide. IOP dropped by 2.98 mmHg (SEM 0.28 mmHg), corresponding to a 17.19% (SEM 1.56%) reduction. The decrease in IOP correlated with the decrease of OPA (r(2) = 0.4, P < 0.0001). Ocular pulse amplitude measurements are influenced by oral administration of acetazolamide. There was a decrease in the pulsatile component of choroidal blood flow and in IOP in both htPOAG and healthy controls. This needs to be taken into account for measurement of OPA with dynamic contour tonometry.

The Relationship between Intraocular Pressure and Glaucoma in a Defined Population

Purpose: To provide data on the prevalence of ocular hypertension and glaucoma and on the diagnostic validity of tonometry. Methods: In this cross-sectional, population-based study, 4,927 subjects over 40 years of age were examined. Each subject underwent a complete ocular examination as part of the Egna-Neumarkt Glaucoma Study. These examinations were carried out by trained, quality-controlled ophthalmologists, according to a predetermined standard protocol that included a medical interview, applanation tonometry, computerized perimetry, optic nerve head examination and other ocular measurements. The following data were recorded: mean IOP, prevalence of ocular hypertension, primary open-angle glaucoma and normal tension glaucoma. Sensitivity, specificity and the predictive value of the tonometric test, as well as the distribution of IOP in the different groups were also determined. Results: The overall prevalence of ocular hypertension, hypertensive primary open-angle glaucoma and normal tension glaucoma corresponded to 2.1, 1.4 and 0.6%, respectively. Other types of glaucoma accounted for a further 0.9%. The sensitivity and specificity of the tonometric test in recognizing glaucoma (cut-off between 21 and 22 mm Hg) were, respectively, 80.1 and 97.8%. The predictive values of the positivity and negativity of the test were 52.1 and 99.4%, respectively. Conclusions: The prevalence of ocular hypertension and glaucoma was similar to that found in several recent epidemiological studies. Tonometry alone is obviously not sufficient to ascertain or to exclude the presence of glaucoma; its diagnostic validity however is high and should never be underestimated. An elevated IOP is the main risk factor for glaucoma, with the degree of risk increasing as the level of IOP increases.

Diurnal Intraocular Pressure Curves in Healthy Rhesus Macaques (Macaca mulatta) and Rhesus Macaques With Normotensive and Hypertensive Primary Open-Angle Glaucoma

The authors identify any diurnal intraocular pressure (IOP) variation in healthy Cayo Santiago macaques, as well as Cayo Santiago macaques with normotensive and hypertensive primary open-angle glaucoma (POAG), to further evaluate their potential value as a model for human POAG. Twenty-four monkeys (eight animals each of the healthy control, normotensive glaucoma, and hypertensive glaucoma groups) were sedated with ketamine hydrochloride and the IOP measured hourly from 8:00 AM until 3:00 PM with a Tonopen XL applanation tonometer (Mentor, Norwell, MA, U.S.A.). Mean IOP time profiles, mean IOPs at each observation time, and linear trends in mean IOP over time were compared among groups. Intraocular pressure rate-of-change over time and residual variation about the regression line for each individual eye were analyzed. Cup/disc ratio (C/D) was compared with baseline IOP, IOP profile mean and slope, and IOP residual variation. A significant group and time effect on mean IOP (p = 0.0001 and 0.011, respectively), with highest values at 2:00 PM or 3:00 PM, and a significant increasing linear trend in mean IOP over time in the hypertensive group were observed (p = 0.012). Intermediate readings between control and hypertensive mean IOPs were identified for the normotensive glaucoma group. The biggest range of IOP variation was found in the hypertensive glaucoma monkeys. Higher variations in IOP did not lead to an increase in C/D. This study provides evidence that the Cayo Santiago macaques are a valuable model for human normotensive and hypertensive POAG.

Impact of Intraocular Pressure on Venous Outflow from the Globe

Increasing focus on so-called normal-tension glaucoma has raised questions concerning the mechanism by which intraocular pressure (IOP) may play a role in the pathophysiology of glaucomatous optic neuropathy. However, examination of pressure-relationships suggests that an increase of a few mm Hg in IOP within the normal-tension range may double the magnitude of one important physiologic parameter, the magnitude of the intravascular waterfall effect at the exit of the central retinal vein (CRV) from the globe. This, in turn, increases the pulsatility or the velocity and turbulence of blood flow, depending on the extent of the restriction to venous outflow at the passage of the CRV through the lamina cribrosa. In the absence of such restriction, increased CRV pulsatility, especially in combination with brief IOP spikes, can be expected to cause foci of microvascular collapse in the optic nerve head. These foci can be converted to permanent vascular defects depending on additional risk factors, such as abnormal blood rheology ro platelet aggregation. Greater than normal laminal restrictions can, on the other hand, reduce perfusion pressure and can cause turbulence-induced endothelial damage and thickening of the CRV wall, ultimately further reducing perfusion pressure. These considerations suggest the hypothesis that the size and configuration of the venous outflow channel through the lamina cribrosa is a primary determinant of the extent of vascular and ultimately neuronal damage that occurs at a given IOP level in normal-tension and hypertensive primary open-angle glaucoma.