Choroidal Blood Flow (choroidal + blood_flow)

Distribution by Scientific Domains


Selected Abstracts


Choroidal blood flow and retinal ganglion cell function in early glaucoma

ACTA OPHTHALMOLOGICA, Issue 2009
D MARANGONI
Purpose To assess subfoveal choroidal blood flow in patients with early manifest glaucoma (EMG) and to compare blood flow with functional measures of retinal ganglion cell (RGC) integrity. Methods Subfoveal choroidal blood flow was determined by confocal, real-time laser Doppler flowmetry in 25 EMG patients (<-6 dB Humphrey mean deviation, age range: 42-64 years, visual acuity: 0.8-1.0) and in 20 age-matched controls. All patients had a therapeutically (topical beta-blockers with or without a prostaglandin) controlled intraocular pressure (IOP <20 mmHg). Subfoveal choroidal blood volume (ChBVol), velocity (ChBVel) and flow (ChBF) were determined as the average of three 60 sec recordings with changes in the DC < 10% between the recordings (DC measures the intensity of the light scattered by the tissue and red blood cells in the illuminated volume). In all patients and controls pattern electroretinograms (PERGs) were recorded according to a standardized protocol. Results In EMG patients, average ChBVel and ChBF were reduced by 31 and 35%, respectively (p <0.01) compared to control values. No significant difference in ChBVol was found between the two groups. PERG amplitudes were reduced by 40% (p <0.01) in EMG patients compared to controls. No correlation was found between anyone of the choroidal flow parameters and PERG data or IOP values. Conclusion The results suggest a significant alteration of subfoveal choroidal hemodynamics in EMG patients, involving both ChBVel and ChBF. These changes do not appear to be associated with the severity of functional retinal ganglion cell loss. Our findings may have implications for the pathophysiology of early glaucomatous damage and its treatment. [source]


Free fatty acids exert a greater effect on ocular and skin blood flow than triglycerides in healthy subjects

EUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 8 2004
M. Bayerle-Eder
Abstract Background, Free fatty acids (FFAs) and triglycerides (TGs) can cause vascular dysfunction and arteriosclerosis. Acute elevation of plasma FFA and TG concentration strongly increase ocular and skin blood flow. This study was designed to discriminate whether FFA or TG independently induce hyperperfusion by measuring regional and systemic haemodynamics. Methods, In a balanced, randomized, placebo-controlled, double-blind, three-way, crossover study nine healthy subjects received either Intralipid® (Pharmacia and Upjohn, Vienna, Austria) with heparin, Intralipid® alone or placebo control. Pulsatile choroidal blood flow was measured with laser interferometry, retinal blood flow and retinal red blood cell velocity with laser Doppler velocimetry, and skin blood flow with laser Doppler flowmetry during an euglycaemic insulin clamp. Results, A sevenfold increase of FFA during Intralipid®/heparin infusion was paralleled by enhanced choriodal, retinal, and skin blood flow by 17 ± 4%, 26 ± 5% (P < 0·001), and 47 ± 19% (P = 0·03) from baseline, respectively. In contrast, a mere threefold increase of FFA by infusion of Intralipid® alone did not affect outcome parameters, despite the presence of plasma TG levels of 250,700 mg dL,1; similar to those obtained during combined Intralipid®/heparin infusion. Systemic haemodynamics were not affected by drug infusion. Conclusions, Present findings demonstrate a concentration-dependent increase in ocular and skin blood flow by FFA independently of elevated TG plasma concentrations. As vasodilation of resistance vessels occur rapidly, FFA may play a role in the development of continued regional hyperperfusion and deteriorate microvascular function. [source]


2231: Age-related modifications in RPE cells

ACTA OPHTHALMOLOGICA, Issue 2010
E MANNERMAA
Age-related macular degeneration (AMD) is a multi-factorial polygenetic aging disease. It has been shown that RPE dysfunction predisposes neural retinal dysfunction and the development of choroidal neovascularization. The pathogenesis of age-related macular degeneration (AMD) essentially involves chronic oxidative stress, increased accumulation of lipofuscin in retinal pigment epithelial (RPE) cells and extracellular drusen formation, as well as the presence of chronic inflammation. The capacity to prevent the accumulation of cellular cytotoxic protein aggregates is decreased in senescent cells which may evoke lipofuscin accumulation into lysosomes in postmitotic RPE cells. This presence of lipofuscin decreases lysosomal enzyme activity and impairs autophagic clearance of damaged proteins which should be removed from cells. Proteasomes are another crucial proteolytic machine which degrades especially cellular proteins damaged by oxidative stress. The cross-talk between lysosomes, autophagy and proteasomes in RPE cell protein aggregation, their role as a possible therapeutic target and their involvement in the pathogenesis of AMD is discussed. In addition, age related changes in Bruch's membrane and choroidal blood flow may take part in the pathogenesis of AMD. This will be also discussed. [source]


4413: Analysis of gene expression in acute ischemic neuroretinas : a genome-wide screen discriminating occlusion (BRVO) versus laser effects in rats

ACTA OPHTHALMOLOGICA, Issue 2010
C OROPESA
Purpose Identification of genes differentially regulated in rat neuroretinas submitted to an experimental acute branch retinal vein occlusion (BRVO), to a laser treatment, or to no treatment at all. Methods We have developed an in vivo experimental model of venous occlusion by photodynamic thrombosis in rat retinas. After anaesthesia, a sodium fluorescein solution was injected in rat tail 15 minutes before laser treatments. To induce ischemia in tested retina, venous sites adjacent to the optic nerve head were photocoagulated with an argon laser. In one group of tested animals, the retina was exposed to laser treatment at sites located between major vessels. As this treatment may have an effect upon choroidal blood flow, control eyes were not subjected to laser treatment. RNAs were isolated from the neuroretina 30 minutes post treatments, and processed for Affymetrix gene-chip analysis. Results Genome-wide screen enabled us to identify 308 and 348 genes which were up- or down-regulated, respectively, by BRVO and laser treatment only. When we compared the transcriptomes of retinas subjected to vessel occlusion or laser treatment to the control one, we found that the expression profiles of, respectively, 116 and 126 genes were specifically modified. The majority of the up- and down-regulated genes encode proteins involved in different aspects of early stress response, neuroprotection, inflammation and apoptosis. Conclusion Our microarray analysis revealed changes in gene expression bearing similarities to gene expression results from other ischemia models. Furthermore, it revealed that laser treatment may have an unreported impact on retina's metabolism. [source]


2453: Optic disc in the picture: novel imaging techniques

ACTA OPHTHALMOLOGICA, Issue 2010
W DREXLER
Purpose Advances in light sources and detection technologies enabled a paradigm shift in retinal OCT imaging performance. ,Snap-shot OCT' enabling isotropic sampling over 512x512x1024 voxels with 600 frames/second in less than a second is now possible. Methods The resolution advantage in conjunction with full volumetric sampling has enabled the development of more informative indices of axonal damage in glaucoma compared with measurements of RNFL thickness and cup to disc ratio provided by other devices. A novel mapping method was developed, the three-dimensional minimal distance (3D-MDM) as the optical correlate of true retinal nerve fiber layer thickness around the optic nerve head region. In a preliminary study relation between the cross-sectional areas of the retinal nerve fiber layer and the optic nerve was found to be a sensitive measure of axon loss. Results In addition to all the major layers of the retina, the entire choroid down to the lamina cribrosa and sclera can now be visualized. This enables unprecedented information about choroidal vasculature without any contrast agents, choroidal thickness and will enable quantification of choroidal blood flow in the near future. Furthermore this technique allows tissue to be imaged in vitro with an image resolution better than 1-2 µm, allowing to image single cells and detect pre-apoptotic signatures using OCT. RGC-5 cells were imaged using a sampling rate 1024x512x1024 voxel at 800 nm central wavelength and a bandwidth of 230 nm, enabling the detection of optical signatures at different pre-stages of programmed cell death. Conclusion Significantly increased OCT imaging speed and tissue penetration might enable novel insights and diagnostic opportunities in the diagnosis and therapy monitoring of glaucoma. Commercial interest [source]


2326: Influence of change in body position on choroidal blood flow in patients with obstructive sleep apnea syndrome

ACTA OPHTHALMOLOGICA, Issue 2010
A ALMANJOUMI
Purpose Obstructive sleep apnea syndrome (OSA) has been reported to be associated with ischemic and glaucomatous optic neuropathy (especially normal tension glaucoma). OSA per se is able to generate hypertension, atherosclerosis and autonomic dysfunction, all conditions possibly interacting with ocular vascular regulation. The aim of our study was to characterize the choroidal vascular reactivity to change in body position in OSA patients, as compared with matched healthy control subjects. Methods Eighteen newly diagnosed OSA patients were included in this prospective study. Control subjects were matched with OSA patients for body mass index (BMI), gender and age. At the screening visit, each subject underwent a general exam, cardiovascular, neurologic and ophthalmological examinations, and overnight polysomnography. The LDF instrument used in this study to measure subfoveal choroidal blood flow (ChBF), ChBVel , velocity (kHz); and volume, ChBVol (in arbitrary units, AU) Vascular choroidal reactivity was tested during the change in body position from the sitting to the supine position (10 min). Results OSA patients exhibited a similar choroidal reactivity during change in body position than controls with increased ChBVel (+15%), decreased ChBVol (-11.6%), and unchanged ChBF. IOP increased by 14.2% in the supine position whereas ocular perfusion pressure remained stable. Conclusion This prospective comparative study showed for the first time unimpaired choroidal vascular reactivity in otherwise healthy OSA patients. This suggests OSA patients, without comorbidities, has long-term adaptive mechanisms active in ocular microcirculation. [source]


Effect of systemic moxaverine on ocular blood flow in humans

ACTA OPHTHALMOLOGICA, Issue 7 2009
Hemma Resch
Abstract. Purpose:, A number of common eye diseases are associated with ocular perfusion abnormalities. The present study aimed to investigate whether systemically administered moxaverine improves ocular blood flow. Methods:, Sixteen healthy volunteers were studied in this randomized, double-masked, placebo-controlled, two-way crossover study. Moxaverine in a dose of 150 mg was administered i.v. Ocular haemodynamic parameters were measured before and after drug administration. Retinal arterial and venous diameters were measured with a retinal vessel analyser. Retinal blood velocity was assessed using laser Doppler velocimetry and choroidal and optic nerve head blood flow was measured with laser Doppler flowmetry. Results:, Moxaverine increased choroidal blood flow (22.6 ± 27.9%), an effect which was significant versus placebo (p = 0.015). Red blood cell velocity in retinal veins tended to increase by 13.6 ± 13.3% after infusion of moxaverine, but this effect was not significant compared with placebo (p = 0.25). In the optic nerve head moxaverine also tended to increase blood flow (11.8 ± 12.7%), but, again, this effect was not significant versus placebo (p = 0.12). Neither moxaverine nor placebo had an effect on retinal arterial diameters. In retinal veins moxaverine tended to induce vasodilation (2.6 ± 2.8%) and to increase blood flow (19.6 ± 16.5%), but these effects were not significant (both p = 0.12). Conclusions:, The present study indicates an increase in choroidal blood flow after systemic infusion of a single dose of moxaverine in healthy subjects. Further studies are warranted to investigate whether these effects are also seen after longterm treatment in patients with ocular vascular disease. [source]


Ocular haemodynamic changes after single treatment with photodynamic therapy assessed with non-invasive techniques

ACTA OPHTHALMOLOGICA, Issue 6 2009
Noemi Maar
Abstract. Purpose:, To investigate in patients with neovascular age-related macular degeneration (ARMD) the changes in ocular perfusion caused by single treatment with photodynamic therapy (PDT) by different non-invasive methods; to evaluate correlations between relative changes of ocular haemodynamic parameters after PDT among each other and compared to morphological parameters; and to assess this in relation to early changes of visual acuity. Methods:, Study population: 17 consecutive patients with subfoveal choroidal neovascularization (CNV) caused by ARMD scheduled for PDT without previous PDT treatment (four patients with predominantly classic CNV and 13 patients with occult CNV). Observation procedures: best-corrected visual acuity (before PDT, 6 and 8 weeks after PDT), fundus photography, fluorescein angiography, haemodynamic measurements with laser Doppler flowmetry (LDF), laser interferometry and ocular blood flow (OBF) tonometry (baseline and 1, 2, 6 and 8 weeks after treatment). Main outcome measures: choroidal blood flow (CHBF), fundus pulsation amplitude (FPA), pulsatile ocular blood flow (POBF), visual acuity. Changes smaller than 20% were considered clinically irrelevant. Results:, Ocular haemodynamic parameters did not change significantly in the follow-up period. Changes of haemodynamic parameters showed no correlation to treatment spot, morphological changes or visual acuity. Changes of visual acuity were comparable to results of earlier studies. Conclusion:, Single treatment with PDT did not modify ocular blood flow parameters above 20% as assessed with different non-invasive methods. [source]


Complex regulation of choroidal blood flow during combined changes in blood pressure and IOP

ACTA OPHTHALMOLOGICA, Issue 2009
L SCHMETTERER
Purpose In the recent years it has been shown that the human choroid shows some regulatory capacity during an artifical increase in intraocular pressure (IOP) as well as during an exercise induced increase in mean arterial pressure (MAP). The purpose of the present study was to test the hypothesis that human choroidal blood flow (ChBF) may depend, not only on ocular perfusion pressure (OPP), but also on absolute levels of MAP and IOP. Methods In a clinical study in 28 helathy subjects OPP was varied by elevating IOP during a squatting-induced increase in MAP. IOP was raised in stepwise increments by using the suction cup method. Subfoveal choroidal blood flow (VhBF, laser Doppler flowmetry), MAP, and IOP were assessed, and OPP was calculated as (2/3)(MAP - IOP). For correlation analysis, data from all subjects were pooled according to IOP and MAP values, and correlation analyses were performed. Results When data were grouped according to IOP, no correlation was observed between ChBF and MAP; but ChBFs were lower, the higher the IOP (P < 0.001). When data were grouped according to MAP, a significant correlation was found between ChBF and IOP (P < 0.001), but correlations were independent of MAP. Conclusion These data confirm previously published observations that the choroid shows some regulatory capacity during changes in OPP. In addition, the data indicate that the choroid regulates its blood flow better during exercise-induced changes in MAP than during an experimental increase in IOP. [source]


Evaluation of choroidal blood flow after treatment of retinal diseases

ACTA OPHTHALMOLOGICA, Issue 2009
C CHIQUET
Purpose this review aims to summarize studies which assessed the effect of treatment on choroidal blood flow. Methods this presentation will focus on studies using the laser Doppler flowmeter for the analysis of choroidal blood flow parameters (velocity, volume and flow) before and after treatment. Therapies have been assessed in different ocular disease, such as age-related macular degeneration (laser photocoagulation therapy, photodynamic therapy, transpupillary thermotherapy, sildenafil citrate, niacin, pentoxifylline), diabetes mellitus (panretinal photocoagulation, intravenous C-peptide infusion), retinal vein occlusions (isovolemic hemodilution), macular edema (diclofenac), inflammation (corticosteroid), retinal detachment (surgery) or glaucoma (nimodipine, endothelin receptor antagonist, bimatoprost, timolol, trabeculectomy). Results this paper will give insight to the effects of laser treatment (laser photocoagulation, photodynamic therapy), surgery (scleral buckling, trabeculectomy, ocular anesthesia) or systemic drugs on the choroidal blood flow. Methodological considerations will be analyzed, such as the calculation of the sensitivity of the experiments, the comparisons of different groups with or without randomization. Conclusion laser Doppler flowmetry is a useful and a non invasive technique to study the effect of treatment on choroidal blood flow. In ocular disease, investigators should be aware of the tissue scattering changes associated with a retinal or choroidal disease and the necessity of a controlled foveal fixation. [source]


Age-related macular degeneration: hemodynamic changes

ACTA OPHTHALMOLOGICA, Issue 2009
CJ POURNARAS
Purpose Metabolic changes of the RPE associated to the dysfunction of choriocapillaries(CC)/RPE complex may induces the AMD-related changes. Additional vascular changes in the choroid potentially have deleterious effects on the RPE. Methods Quantification of CC number and lumen diameters in cross sections and alkaline phosphatase (APase) flat-embedding technique, expressing high constitutive APase activity in choriocapillaris and choroidal veins on human RPE/Bruch's Membrane/CC complex, significantly contributed to the analysis of the choroidal vasculature. Laser Doppler flowmetry (LDF) data provided additional information on the assessment of hemodynamic changes in AMD. Results Choroidal vascular density reduction and significant vasoconstriction of the choriocapillaries, occurs during the evolution of AMD. In eyes with geographic atrophy, the RPE degenerates first while CC loss is secondary to RPE degeneration. In eyes with exudative AMD, degeneration of the CC layer occurs while RPE is still functional. LDF data indicated choroidal blood flow decrease according to age and the degree of severity of AMD; the decrease in flow preceding the formation of choroidal CNV, strongly suggest that these changes may have a role in the development of CNV. As a result of vascular dysfunction, the choroidal blood flow is dysregulated in patients with neovascular AMD. The choroidal watershed zone (WZ) courses through the fovea more often in patients suffering from AMD than in age-matched controls, particularly in the presence of CNV. Choroidal neovascularisation usually arises within these WZ. Conclusion The role of choroidal ischemia in the pathophysiology of AMD is supported by the observed choroidal microcirculation anatomical and fucntional abnormalities. [source]


Subfoveal choroidal blood flow and central retinal function in retinitis pigmentosa

ACTA OPHTHALMOLOGICA, Issue 2009
B FALSINI
[source]


Autoregulation in the choroid

ACTA OPHTHALMOLOGICA, Issue 2009
S ORGUL
Purpose To compare subfoveal choroidal blood flow (ChBF) in sitting and supine position in normal volunteers. Methods ChBF was measured with laser Doppler flowmetry in 22 healthy volunteers (mean age ± SD: 24 ± 5 years). Six independent measurements of choroidal blood flow were obtained in one randomly selected eye of each subject. Subsequently, the subjects assumed a supine position for 30 minutes and a new series of 6 measurements was obtained. Parallel hereto, systemic blood pressure and intraocular pressure were measured. Ocular perfusion pressure (OPP) was calculated based on formulas derived from ophthalmodynamometric studies. The influence of changing OPP on the change in ChBF was assessed in a linear regression analysis. Results The coefficient of variation for ChBF was 10.28% and 9.58% in the sitting and the supine position respectively. ChBF decreased by 6.6% (p=0.0017) in the supine position. The estimate for ophthalmic blood pressure in the supine position was adjusted to obtain a result of no change in OPP for no change in ChBF, yielding an average decrease for the estimate of OPP of 6.7% (p=0.0002). Change in OPP correlated significantly with change in ChBF (R2: 0.20; p=0.036) with a slope for the regression line of 1.04. Conclusion The comparable degree of change in ChBF and OPP and the linear relationship between the two parameters suggest a passive response of the choroidal circulation to the posture change. In contrast, the OPP estimates suggest a marked buffering of the change in perfusion pressure by the carotid system, compatible with a close control of the gradient in perfusion pressure between the heart and its branches within the carotid system. [source]


Choroidal blood flow and retinal ganglion cell function in early glaucoma

ACTA OPHTHALMOLOGICA, Issue 2009
D MARANGONI
Purpose To assess subfoveal choroidal blood flow in patients with early manifest glaucoma (EMG) and to compare blood flow with functional measures of retinal ganglion cell (RGC) integrity. Methods Subfoveal choroidal blood flow was determined by confocal, real-time laser Doppler flowmetry in 25 EMG patients (<-6 dB Humphrey mean deviation, age range: 42-64 years, visual acuity: 0.8-1.0) and in 20 age-matched controls. All patients had a therapeutically (topical beta-blockers with or without a prostaglandin) controlled intraocular pressure (IOP <20 mmHg). Subfoveal choroidal blood volume (ChBVol), velocity (ChBVel) and flow (ChBF) were determined as the average of three 60 sec recordings with changes in the DC < 10% between the recordings (DC measures the intensity of the light scattered by the tissue and red blood cells in the illuminated volume). In all patients and controls pattern electroretinograms (PERGs) were recorded according to a standardized protocol. Results In EMG patients, average ChBVel and ChBF were reduced by 31 and 35%, respectively (p <0.01) compared to control values. No significant difference in ChBVol was found between the two groups. PERG amplitudes were reduced by 40% (p <0.01) in EMG patients compared to controls. No correlation was found between anyone of the choroidal flow parameters and PERG data or IOP values. Conclusion The results suggest a significant alteration of subfoveal choroidal hemodynamics in EMG patients, involving both ChBVel and ChBF. These changes do not appear to be associated with the severity of functional retinal ganglion cell loss. Our findings may have implications for the pathophysiology of early glaucomatous damage and its treatment. [source]


Effect of nitric oxide synthase inhibition and nerve stimulation frequency on autonomous choroidal vasodilation

ACTA OPHTHALMOLOGICA, Issue 2009
HA REITSAMER
Purpose To investigate the effect of non selective nitric oxide synthase inhibition and the influence of nerve stimulation frequencies on parasympathetic choroidal vasodilation. Methods Stimulations of parasympathetic nerve fibers of the greater petrosal nerve with 8 and 20 Hz were performed simultaneously with continuous measurements of intraocular pressure (IOP), choroidal blood flow (ChorBF), orbital venous pressure (OVP) and arterial pressure at the eye level (MAP). Stimulations were perfomed at baseline, after non selective inhibition of all nitric oxide synthases with L-NAME and after systemic administration of atropine in an anesthetized acute rabbit model. Results Baseline values (mean ± sem, n=6): MAP 66.9 ± 1.8 mmHg, IOP 17.3 ± 0.8 mmHg, ChorBF 467 ± 54 P.U. Facial nerve stimulation with 8 Hz under baseline conditions causes a significant increase of ChorBF 660 ± 80 P.U. and IOP 20.7 ± 1.6 mmHg and a non significant decrease of MAP 61.1 ± 5.0 mmHg. The effects of 20 Hz stimulation did not differ significantly from the 8 Hz results (MAP 68.1 ± 5.0, IOP 22.86 ± 2.0, ChorBF 688 ± 73). Non selective inhibition of the nitric oxide synthases with L-NAME (20 mg/kg) changed the vasodilatory effects of the two stimulation frequencies. The relative effect of 8 Hz stimulation was significantly smaller than the effect of 20 Hz stimulation. However, baseline blood flow after L-NAME was lower than under baseline conditions. Conclusion 8Hz and 20 Hz parasympathetic stimulation had similar effects before but not after non selective NOS inhibition. However, no dose of L-NAME completely suppressed the effect of parasympathetic stimulation. [source]


Effects of moxaverine on ocular blood flow in patients with age-related macular degeneration, patients with primary open angle glaucoma and in healthy controls

ACTA OPHTHALMOLOGICA, Issue 2009
B PEMP
Purpose Several common eye diseases including age-related macular degeneration (AMD) and primary open angle glaucoma (POAG) are associated with ocular perfusion abnormalities. Moxaverine has been shown to increase ocular blood flow in young, healthy volunteers after intravenous administration. The present study investigated whether moxaverine alters ocular blood flow in elderly patients with AMD or POAG and in healthy control subjects. Methods 20 patients with AMD, 20 patients with POAG and 20 age-matched healthy subjects were included in this trial. 150 mg moxaverine (Ursapharm, Saarbrücken, Germany) was administered intravenously over 30 minutes. Systemic haemodynamics, retinal vessel diameters, choroidal, optic nerve head and retrobulbar blood flow were measured before and up to 90 minutes after drug administration. Results Administration of moxaverine increased choroidal blood flow by 8.7 ± 21.8% (p=0.012) and optic nerve head blood flow by 12.9 ± 33.3% (p=0.021). Additionally, an increase in the mean flow velocities of posterior ciliary arteries (24.8 ± 34.7%, p<0.001) and in the ophthalmic artery (23.3 ± 33.5%, p<0.001) was found after administration of moxaverine. However, no differences were found between the 3 study groups. No significant change of retinal vessel diameters was observed. Conclusion The present study indicates an increase of ocular blood flow after systemic administration of a single dose of moxaverine in patients with POAG, patients with AMD and in age-matched healthy controls. Further studies are needed to investigate possible beneficial effects after long-term treatment in patients with ocular diseases associated with hypoperfusion. [source]


Influence of Ginkgo biloba on ocular blood flow

ACTA OPHTHALMOLOGICA, Issue 4 2007
Barbara Wimpissinger
Abstract. Purpose:, To investigate the effect of Ginkgo biloba extract (EGb761) on ocular blood flow. Methods:, This randomized, double-masked, placebo-controlled, two-way crossover study included 15 healthy male volunteers. Measurements were taken with laser Doppler flowmetry, laser Doppler velocimetry, a retinal vessel analyser, laser interferometry and applanation tonometry, before and up to 3 hours after oral intake of 240 mg EGb761. Results:, At baseline, no significant differences in ocular and systemic haemodynamic parameters were observed between the two study days. Ginkgo biloba significantly decreased retinal venous diameters (p < 0.05 versus baseline), but there was no significant difference between the two groups. Blood pressure, retinal arterial and venous diameters, choroidal blood flow, fundus pulsation amplitude, intraocular pressure and retinal blood flow remained unchanged in both groups and did not differ between groups. Optic nerve head blood flow significantly increased in response to Ginkgo biloba (p < 0.002 versus baseline), but this effect was not significant compared with that of placebo. Conclusions:, The results of this study indicate that a single administration of Ginkgo biloba does not influence ocular blood flow to a relevant degree. Whether the drug may influence ocular blood flow in patients with ocular vascular disease after longterm treatment remains to be investigated in a randomized, placebo-controlled clinical trial. [source]


A comparison of the effects of dorzolamide/timolol fixed combination versus latanoprost on intraocular pressure and pulsatile ocular blood flow in primary open-angle glaucoma patients

ACTA OPHTHALMOLOGICA, Issue 6 2004
I. Janulevicienė
Abstract. Purpose:,To evaluate the effects of dorzolamide/timolol fixed combination (D/T) compared to latanoprost on intraocular pressure (IOP) and pulsatile ocular blood flow (POBF) in primary open-angle glaucoma (POAG) patients. Methods:,Thirty patients with POAG were randomized in an open-label, cross-over study. Intraocular pressure reduction was achieved by 4 weeks medical therapy with D/T twice daily or latanoprost 0.005% dosed once in the evening. During a 4-week run,in and a 4-week wash-out period between study arms, patients ceased use of all other glaucoma medications and used timolol maleate 0.5% twice daily. Primary efficacy variables were IOP and POBF. Results:,There was no difference in baseline IOP and POBF parameters between the two study arms. Both D/T and latanoprost statistically significantly reduced IOP by 4.6 mmHg (p < 0.0001) and 3.75 mmHg (p < 0.0001) and increased POBF by 2.048 µl/second (p = 0.0030) and 2.147 µl/second (p = 0.0009), respectively. Repeated measures anova detected significant changes in POBF with treatment (p = 0.0361). Dorzolamide/timolol fixed combination statistically significantly increased pulse volume by 0.767 µl (p = 0.0087), while latanoprost therapy had no significant effect (p = 0.2407). Conclusions:,Both drugs had similar effects in terms of IOP reduction. Dorzolamide/timolol significantly increased pulse volume while latanoprost had no effect. Further studies are necessary to establish whether the enhancement of choroidal blood flow can prevent glaucoma progression. [source]