PURPOSE: To perform a descriptive analysis of the effects on ocular blood flow of transpupillary thermotherapy (TTT) for occult subfoveal choroidal neovascular membranes (CNVMs) in age-related macular degeneration (AMD). METHODS: Eleven subjects with occult subfoveal CNVM due to AMD were assessed in a masked fashion by color Doppler imaging (CDI) ...

Twelve compounds of N-nitropyrazoles were studied for their effects on ocular blood flow in rabbits and retinal function recovery in rat eyes after ischemic insults. Of the twelve N-nitropyrazoles examined, nine increased choroidal blood flow while five increased retinal blood flow significantly. On the other hand, all twelve compounds increased ...

OBJECTIVES: To estimate the measuring depth of the blood flow and to establish the vascular contributions to these measurements with scanning laser Doppler flowmetry (SLDF) of the primate anterior optic nerve. METHODS: Optic nerve blood flow in each eye of 8 monkeys was measured using SLDF before and following surgical ...

Optic flow is essential for the perception of self motion and the control of path integration during locomotion. Inverting prisms oriented 15 degrees off vertical in the roll plane were used to experimentally distort optic flow during locomotion. Depending on the direction in which the prisms were rotated, optic flow ...

BACKGROUND/AIM: Blood flow measures acquired using the scanning laser Doppler flowmeter (SLDF) are known to be highly susceptible to spatial and temporal variations of physiological origin. The purpose of this study was to evaluate a local search strategy intended to overcome these intrinsic variations, thereby improving the detection of blood ...

PURPOSE: Intraocular pressure (IOP) measurements vary with different tonometers in irregular corneas. The purpose of our study was to determine the comparability of the ocular blood flow tonometer (OBF) and Tonopen with the Goldmann applanation tonometer (GAT) in measuring IOP in post-keratoplasty eyes. METHODS: The IOP was measured using the ...

PURPOSE: To understand the pathophysiology of central serous chorioretinopathy or bullous retinal detachment in patients under systemic corticosteroid treatment. Little is understood about the mechanism of the development of serous retinal detachment. METHODS: Three patients who had developed central serous chorioretinopathy or bullous retinal detachment during systemic corticosteroid administration were ...

PURPOSE: To investigate retrobulbar blood flow velocities and the effects of topical timolol treatment in eyes with newly detected, previously untreated open angle glaucoma or ocular hypertension. METHODS: Fifteen eyes with open angle glaucoma (OAG) and 12 eyes with ocular hypertension (OH), in the same number of patients, all untreated ...

AIM: To determine whether a newly identified thrombophilia factor, activated factor VII (FVIIa), is associated with retinal vein occlusion (RVO). METHODS: 54 consecutive cases with RVO seen between March and September 1999 were included in the study. 22 cases had central retinal vein occlusion (CRVO) and 32 had branch retinal ...

PURPOSE: In this study the acute effect of the topically-delivered non-selective beta-blockers timolol and carteolol, and the selective beta-blocker betaxolol, were evaluated with respect to ocular blood flow, intraocular pressure (IOP) and vessel resistance in rabbits' eyes. METHODS: In a double masked randomized design, one eye of each subject (n ...

BACKGROUND: The reported effect of gender on retinopathy of prematurity has been controversial. The goal of this study was to determine the effect of gender on oxygen-induced retinopathy in a mouse model. METHODS: Oxygen-induced retinopathy was produced in C57BL6 mice by exposure to 75% oxygen from postnatal day (P) 7 ...

The physiologic mechanism of photocoagulation can been seen in the following steps. The physical light energy is absorbed in the melanin of the retinal pigment epithelium. The adjacent photoreceptors are destroyed and are replaced by a glial scar and the oxygen consumption of the outer retina is reduced. Oxygen that ...

The most successful method for measuring absolute blood flow rate through the retinal circulation has been the use of radioactive microspheres. The purpose of this study was to develop a microsphere method that did not have the drawbacks associated with radioactivity and to use this method to make measurements of ...

A prior study found that inhibition of nitric oxide synthase with L-NAME causes a large, rapid decrease in IOP in anesthetized rabbits. In this follow-up study we sought to determine if this hypotensive effect was due to decreased aqueous production, possibly caused by ciliary vasoconstriction. Two protocols were performed in ...

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 ...

BACKGROUND: The aim of the present study was to investigate the association between systemic blood pressure and retinal blood flow in healthy young subjects. METHODS: Three independent study cohorts were included. A cross-sectional study was performed in 420 young male subjects with systolic blood pressure < 160 mmHg and diastolic ...

OBJECTIVE: The purpose of this study was to investigate whether the effect of learning and the reproducibility of measurements varied between the two methods of application (hand-held or slit-lamp mounted) of the ocular blood flow (OBF) tonometer. METHOD: Five consecutive measurements by each method were taken at one examination session ...

Diabetic retinopathy is the leading cause of blindness in working age individuals in the United States. Breakdown of the blood-retinal barrier is one of the earliest events in the progression of diabetic retinopathy. Ideally, therapeutic measures would be directed at this early stage, but there are few sensitive, quantitative methods ...

PURPOSE: To examine the relation between perfusion of the optic nerve head and visual field defects in glaucomatous patients. METHODS: A study was performed on 94 patients affected with primary open-angle glaucoma. The optic nerve head blood flow was measured by means of a scanning laser Doppler flowmeter (Heidelberg Retina ...

Factors other than intraocular pressure (IOP) elevation must be involved in initiation and progression of glaucoma. An additional element in disease causation may be ischemia in the retina and optic nerve head. Ischemic damage to neurons in the CNS is similar mechanistically and histopathologically to changes seen in glaucoma. Further, ...

PURPOSE: To study the effects of topically applied nipradilol, an alpha-beta blocker recently developed in Japan as an ocular hypotensive drug, on retinal blood flow (RBF) in healthy volunteers. METHODS: Seven healthy volunteers (mean age, 33 years) underwent measurement of RBF using a newly developed stabilized laser Doppler velocimetry system. ...

PURPOSE: To investigate the relationship between choriocapillaris blood flow and blood flow through an overlying choroidal neovascularization, as it relates to photocoagulation-induced changes in the choriocapillaris circulation. METHODS: A theoretical model that simulates the blood flow in the choriocapillaris and choroidal neovascularization of the human eye was developed, based on ...

PURPOSE: To establish the effect of photodiode sensitivity on the DC (brightness) value and the resultant blood flow measurements of retina and rim tissue using a scanning laser Doppler flowmeter (SLDF). METHODS: The sample consisted of one eye of each of 15 healthy subjects (mean age 27.8 +/- 6.1 years). ...

PURPOSE: Previous studies have shown that adenosine agonists are effective in reducing intraocular pressure (IOP). However, the mechanism(s) responsible for this ocular hypotensive effect has not been established. This study evaluates the relative contribution of changes in aqueous flow and outflow facility associated with the ocular hypotensive response to the ...

The aim of the present study was to assess and to compare the orbital and retinal vascular flow dynamics and resistance in patients with homozygous sickle cell disease with controls by means of duplex and color Doppler ultrasonography. Forty-six patients with homozygous sickle cell disease (SCD) and 20 healthy subjects ...

OBJECTIVE: To determine aqueous humor flow rate in clinically normal dogs, using fluorophotometry. ANIMALS: 20 clinically normal Beagles. PROCEDURE: A study was performed on 5 dogs to establish an optimal protocol for fluorophotometric determination of aqueous humor flow rate. This protocol then was used to measure aqueous humor flow rate ...

PURPOSE: To evaluate the use of the Heidelberg retina flowmeter (HRF) in diagnosing retinal ischaemia following macular branch retinal vein occlusion. METHODS: Ten patients with ischaemic macular branch retinal vein occlusion, as determined by strict fluorescein angiographic criteria, were examined with the HRF. Blood flow, blood volume and blood velocity ...

This survey of methods for assessing ocular hemodynamics in glaucoma and age-related macular degeneration is not complete, but it does cover those likely to be encountered in the literature. A fundamental problem in getting to grips with the ocular blood flow literature is the difficulty in comparing the results of ...

BACKGROUND: The factors that influence pulsatile ocular blood flow (POBF) were evaluated in normal subjects. METHODS: POBF was measured in 80 normal subjects using Langham OBF computerised tonometry. The effect of age, systolic and diastolic blood pressure, refractive error, intraocular pressure, and axial length on POBF was evaluated using multiple ...

BACKGROUND: Pulsatile ocular blood flow (POBF) is a parameter for evaluating choroidal blood flow. POBF in the patients with non-exudative and exudative age related macular degeneration (AMD) was investigated. METHODS: POBF, pulse amplitude (PA), systolic and diastolic blood pressures, intraocular pressure (IOP), refractive error, and axial length were compared among ...

PURPOSE: To investigate the effect of smoking a cigarette on the Heidelberg Retina Flowmeter (HRF) parameter "Flow" at the papilla of healthy young volunteers. METHODS: Three HRF measurements were taken over the papilla (20 x 5, 256 x 64 pixels) in fourteen occasional smokers and in 14 non-smokers. Ten minutes ...

BACKGROUND: The purpose was to study whether any differences exist in the optic nerve head (ONH) and peripapillary retinal blood flow between the two eyes of patients with unilateral exfoliation glaucoma or ocular hypertension (OHT) with exfoliation syndrome. METHODS: This cross-sectional study included 50 patients. All had exfoliation syndrome with ...

BACKGROUND: Regional anesthesia for ophthalmic surgery has been associated with ischemic complications, such as central retinal vascular occlusion, optic atrophy and ischemic optic neuropathy. Impairment of pulsatile ocular blood flow (POBF) may occur with regional orbital anesthesia. In this study we quantified POBF in patients undergoing regional orbital anesthesia. METHODS: ...

OBJECTIVE: To compare the effect on aqueous humor flow and intraocular pressure (IOP) of topically applied 0.2% brimonidine tartrate with topically administered 0.5% timolol maleate, alone and in combination. DESIGN: A randomized, double-masked, placebo-controlled study of 20 human subjects was carried out. The topical drugs were instilled twice daily the ...

PURPOSE: To investigate if retinal blood flow decreases with progression of the disease in Abyssinian cats with progressive retinal atrophy (PRA), to examine if the choroidal blood flow was affected by the disease, and to determine the uptake of glucose and formation of lactate in the outer retina. METHODS: Local ...

Maintenance of an adequate oxygen supply to the retina is critical for retinal function. In species with vascularised retinas, such as man, oxygen is delivered to the retina via a combination of the choroidal vascular bed, which lies immediately behind the retina, and the retinal vasculature, which lies within the ...

PURPOSE: To determine the correlation between transit times of retinal blood flow calculated from fluorescein angiograms and retinal blood flow determined by the microsphere method. METHODS: Two fluorescein angiograms were obtained in each eye of six monkeys, followed by determination of retinal blood flow with labeled microspheres. Angiograms in 10 ...

PURPOSE: To analyze the effect of 0.2% brimonidine eye drops on retinal blood flow of patients with glaucoma. METHODS: Using self-control method and Heidelberg Retina Flowmeter (HRF), we examined the volume, flow and velocity of the superior nasal and temporal, the inferior nasal and temporal artery of retina at baseline ...

Methylmethacrylate castings of the eye microvasculature were prepared from 10 Spargue-Dawley rats and studied by electron microscopy. The choroidal arterioles are larger in diameter than retinal arterioles, and have a shorter course to choroidal capillaries than retinal arterioles to retinal capillaries. Retinal capillaries are extremely thin in diameter and form ...

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 ...

PURPOSE: In vitro models suggest that Heidelberg retina flowmeter (HRF) measurements are affected by changes in photodetector sensitivity. We measured blood flow in a single volume of human retinal tissue in vivo at various sensitivity (DC) levels. METHODS: The peripapillary retinal regions of 12 normal subjects were examined by HRF ...

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 ...

Purpose: We studied the effect of topically applied iganidipine dihydrochloride, a novel water-soluble calcium channel blocker on the blood flow of optic nerve head (ONH), intraocular pressure, and blood pressure in rabbits.Methods: (1) 0.1% iganidipine (20 &mgr;l) was instilled into a normal eye. The change in blood flow in the ...

PURPOSE: To study the effect of topically applied iganidipine dihydrochloride (iganidipine), a novel water-soluble calcium channel blocker, on blood flow in the optic nerve head (ONH), intraocular pressure, and systemic blood pressure in rabbits. METHODS: After 0.1% iganidipine (20 microL) was instilled into normal eyes, the change in ONH blood ...

OBJECTIVE: To investigate blood flow velocity changes, pulsatility and resistivity index values of orbital vessels in Behçet's disease with or without ocular involvement (groups I and II) and healthy volunteers (group III). METHODS: Twenty-five eyes in the first group, 24 eyes in the second group and 24 eyes in the ...

PURPOSE: To evaluate the effects of four commonly used beta-blockers on ocular blood flow in patients with primary open angle glaucoma (POAG). METHODS: Eighty eyes of 40 subjects with POAG were included in the study. Subjects were randomly divided into four groups given timolol maleate 0.50%, betaxolol HCl 0.50%, carteolol ...

PURPOSE: Pseudoexfoliation syndrome is one of the most frequent causes of open-angle glaucoma and is statistically significant associated with a high risk of hypertension, angina, myocardial infarction or stroke and retinal vein thrombosis. The aim of this study was to evaluate the pulsatile ocular blood flow (POBF) in pseudoexfoliation syndrome ...

Elevated plasma free fatty acids (FFA) induce skeletal muscle insulin resistance and impair endothelial function. The aim of this study was to characterize the acute hemodynamic effects of FFA in the eye and skin. A triglyceride (Intralipid 20%, 1.5 ml/min)/heparin (bolus: 200 IU; constant infusion rate: 0.2 IU. kg(-1). min(-1)) ...

PURPOSE: To evaluate the effects of chronic reduction of intraocular pressure (IOP) on ocular hemodynamics. METHODS: Multisite, prospective evaluation of patients requiring trabeculectomy for treatment of glaucoma. Patients were recruited from the glaucoma service of 2 university hospitals. Patients were evaluated prior to surgery and at 3, 6, and 12 ...

PURPOSE: To study retinal capillary blood flow during the acute stage of induced branch retinal vein occlusion (BRVO) in the feline retina and the effect of systemic blood pressure during this event. METHODS: Known fractions of the animal blood cells were labeled by a fluorescent marker and tracked by an ...