Effect of nifedipine on choroidal blood flow regulation during isometric exercise.

Purpose: To determine whether nifedipine, an L-type calcium channel blocker, alters choroidal blood flow (ChBF) regulation during isometric exercise in healthy subjects.

Methods: The study was carried out in a randomized, placebo-controlled, double-masked, two-way crossover design. Fifteen healthy male subjects were randomly assigned to receive either placebo or nifedipine on two different study days.

Posterior optic buttonholing prevents intraocular pressure peaks after cataract surgery with primary posterior capsulorhexis.

Background: The performance of a primary posterior capsulorhexis (PPC) with and without posterior optic buttonholing (POBH) may significantly influence the intraocular pressure (IOP) after cataract surgery in age-related cataract patients.

Methods: The prospective randomized clinical study was performed at the department of Ophthalmology, Medical University of Vienna, Austria. Thirty consecutive cataract patients with bilateral same-day cataract surgery (60 eyes) under topical anesthesia were enrolled.

Effect of NO synthase inhibition on retinal vessel reaction to isometric exercise in healthy humans.

Purpose: It has been shown that retinal blood flow is autoregulated, meaning that flow is independent of perfusion pressure within a certain range. We tested the hypothesis that nitric oxide (NO) synthase inhibition alters the response of retinal arterial and venous vessels during isometric exercise.

Methods: In this study, nine healthy subjects were included.

Choroidal blood flow and progression of age-related macular degeneration in the fellow eye in patients with unilateral choroidal neovascularization.

Purpose: Cardiovascular risk factors such as smoking, hypertension, and atherosclerosis seem to play an important role in the development of choroidal neovascularization (CNV). Recent studies have also provided evidence suggesting that choroidal and retinal blood flow is decreased in patients with AMD. On the basis of these results, the hypothesis for this study was that lower choroidal blood flow is associated with an increased risk of CNV in patients with AMD.

Acute effects of intravenously administered ethanol on retinal vessel diameters and flicker induced vasodilatation in healthy volunteers.

There is evidence from several vascular beds that acute alcohol consumption causes ocular hypotension and peripheral vasodilatation. The current study investigated the effects of intravenously administered ethanol on retinal vessel diameters and on flicker induced retinal vasodilatation. For this purpose, ethanol (0.

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

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.

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).

Effect of primary posterior continuous curvilinear capsulorhexis with and without posterior optic buttonholing on postoperative anterior chamber flare.

Purpose: To evaluate the effect of primary posterior continuous curvilinear capsulorhexis (PCCC) with and without posterior optic buttonholing (POBH) on the anterior chamber reaction after small-incision cataract surgery.

Setting: Department of Ophthalmology, Medical University of Vienna, Vienna, Austria.

Methods: Consecutive patients with age-related cataract having cataract surgery in both eyes under topical anesthesia were prospectively enrolled in a randomized clinical trial.

Effects of vitamin C on hyperoxia-induced reduction of retinal blood flow.

Objective: Breathing of 100% oxygen causes vasoconstriction in retinal vessels paralleled by a decrease in blood flow. The mechanism underlying this effect is still unclear, but may be related to the increased generation of reactive oxygen species during hyperoxia. Thus, the purpose of the present study was to investigate whether vitamin C, an agent with strong antioxidative properties, modifies the retinal vasoconstrictor response to hyperoxia.

Diurnal fluctuation of ocular blood flow parameters in patients with primary open-angle glaucoma and healthy subjects.

Background/aims: To investigate the fluctuations of ocular blood flow parameters over 13 h in patients with primary open-angle glaucoma (POAG) and in healthy eyes, and to relate these fluctuations with variations in intraocular pressure (IOP) and mean ocular perfusion pressure (OPP).

Methods: 15 patients with POAG and 15 control subjects were included. Measurements of systemic blood pressure (SBP), fundus pulsation amplitude (FPA), choroidal blood flow (CHBF), optic nerve head blood flow (ONHBF) and IOP were performed at 08:00, 12:00, 17:00 and 21:00.

Twelve-hour reproducibility of retinal and optic nerve blood flow parameters in healthy individuals.

Purpose: The aim of the present study was to investigate the reproducibility and potential diurnal variation of optic nerve head and retinal blood flow parameters in healthy individuals over a period of 12 hr.

Methods: We measured optic nerve head and retinal blood flow parameters in 16 healthy male non-smoking individuals at five time-points during the day (08:00, 11:00, 14:00, 17:00 and 20:00 hr). Outcome parameters were perimacular white blood cell flux (as assessed with the blue field entoptic technique), blood velocities in retinal veins (as assessed with bi-directional laser Doppler velocimetry), retinal arterial and venous diameters (as assessed with the retinal vessel analyser), optic nerve head blood flow, volume and velocity (as assessed with single point and scanning laser Doppler flowmetry) and blood velocities in the central retinal artery (as assessed with colour Doppler imaging).

Strategies for reducing variance in laser Doppler flowmetry measurements.

Background: Scattering of blood flow data as assessed with laser Doppler flowmetry (LDF) in humans is a problem in many studies using this technique. We set out to reduce variability in LDF data by eliminating the effect of the total returning light level (DC) on LDF parameters in the choroid through partial regression analysis.

Methods: In 20 healthy subjects, choroidal blood flow parameters were measured at different DC values using a portable confocal LDF device.

Anterior chamber depth and change in axial intraocular lens position after cataract surgery with primary posterior capsulorhexis and posterior optic buttonholing.

Purpose: To compare axial position changes of the intraocular lens (IOL) by measuring anterior chamber depth (ACD) after small-incision cataract surgery with primary posterior continuous curvilinear capsulorhexis (PPCCC) and posterior optic buttonholing (POBH) of the IOL and after conventional cataract surgery with phacoemulsification and in-the-bag IOL implantation.

Setting: Department of Ophthalmology, Medical University of Vienna, Austria.

Methods: This prospective comparative study comprised 23 patients (46 eyes) with age-related cataract who had bilateral cataract surgery and implantation of an acrylic IOL (YA-60BB, Hoya).

Macular morphology after cataract surgery with primary posterior capsulorhexis and posterior optic buttonholing.

Purpose: To evaluate possible changes in macular morphology after cataract surgery with combined primary posterior capsulorhexis and posterior optic buttonholing in comparison to conventional in-the-bag intraocular lens (IOL) implantation.

Design: Prospective randomized study.

Methods: Fifty consecutive age-related cataract patients with normal macular morphology and function waiting for bilateral cataract surgery were enrolled.

Comparison of the effect of Viscoat and DuoVisc on postoperative intraocular pressure after small-incision cataract surgery.

Purpose: To evaluate the effect of Viscoat (sodium chondroitin sulfate 4%-sodium hyaluronate 3%) and DuoVisc (Viscoat and Provisc [sodium hyaluronate 1%]) on postoperative intraocular pressure (IOP) after bilateral small-incision cataract surgery.

Setting: Department of Ophthalmology, University of Vienna, Vienna, Austria.

Methods: This prospective randomized study comprised 60 eyes of 30 consecutive patients with age-related cataract in both eyes.

Postoperative course of intraocular pressure after cataract surgery with combined primary posterior capsulorhexis and posterior optic buttonholing.

Purpose: To evaluate the natural course of intraocular pressure (IOP) after cataract surgery with combined primary posterior continuous curvilinear capsulorhexis (PPCCC) and posterior optic buttonholing (POBH) of the intraocular lens (IOL) in adult patients.

Setting: Department of Ophthalmology, Medical University of Vienna, Vienna, Austria.

Methods: Fifty consecutive patients with age-related cataract awaiting cataract surgery under topical anesthesia in both eyes were enrolled prospectively.

Intravenous administration of clonidine reduces intraocular pressure and alters ocular blood flow.

Aim: To evaluate the effect of intravenously administered clonidine on ocular blood flow in healthy volunteers.

Methods: A randomised, double-masked, placebo-controlled, two-way crossover study was performed in 12 healthy young volunteers. Clonidine (0.

Objective assessment of intraocular flare after cataract surgery with combined primary posterior capsulorhexis and posterior optic buttonholing in adults.

Aim: Combining primary posterior capsulorhexis (PPC) and posterior optic buttonholing (POBH) in cataract surgery is an innovative approach to prevent after-cataract formation effectively and to increase postoperative stability of the intraocular lens (IOL). The present study was designed to compare the postoperative intraocular flare after cataract surgery with combined PPC and POBH to conventional in-the-bag implantation of the IOL.

Methods: Fifty consecutive age-related cataract patients with cataract surgery under topical anaesthesia in both eyes were enrolled prospectively into a prospective, randomised clinical trial.

Altered nitric oxide system in patients with open-angle glaucoma.

Objective: To investigate the ocular blood flow response to systemic nitric oxide synthase inhibition in patients with primary open-angle glaucoma.

Methods: In 12 patients with glaucoma and 12 age-matched control subjects, subfoveal choroidal blood flow, optic nerve head blood flow, ocular fundus pulsation amplitude, intraocular pressure, and systemic hemodynamic parameters were measured at baseline and after inhibition of nitric oxide synthase by intravenous administration of NG-monomethyl-L-arginine.

Results: The increase in blood pressure in response to NG-monomethyl-L-arginine was comparable between the 2 study cohorts.

Influence of infusion volume on the ocular hemodynamic effects of peribulbar anesthesia.

Purpose: To test the hypothesis that ocular blood-flow response to peribulbar anesthesia can be reduced by using a smaller volume of anesthetic mixture.

Setting: Departments of Ophthalmology and Clinical Pharmacology, Medical University of Vienna, Vienna, Austria.

Methods: Twenty patients scheduled for bilateral age-related cataract surgery were enrolled in a prospective randomized balanced observer-masked crossover study.

Treatment frequency and visual outcome in subfoveal choroidal neovascularization related to pathologic myopia treated with photodynamic therapy.

Background: The purpose of this study was to examine the influence of treatment frequency on visual acuity of patients with PDT treatment for subfoveal predominantly classic CNV related to pathological myopia.

Design: Retrospective case series.

Methods: Thirty-seven patients with subfoveal predominantly classic CNV caused by pathologic myopia and treated with PDT were included.

ETa-receptor blockade, but not ACE inhibition, blunts retinal vessel response during isometric exercise.

Angiotensin II and endothelin-1 are potent vasoconstrictors that appear to play a role in retinal blood flow regulation. In the present study, we investigated the possible role of the angiotensin and the endothelin system in the regulation of retinal vessel diameters during isometric exercise in healthy humans. The study design was randomized, double-masked, placebo-controlled, and three-way cross over.

Effects of moderate changes in intraocular pressure on ocular hemodynamics in patients with primary open-angle glaucoma and healthy controls.

Purpose: There is some indirect evidence for altered autoregulation in patients with glaucoma, but only a few studies have measured ocular blood flow directly during changes in ocular perfusion pressure. The present study was designed to compare pulsatile choroidal blood flow and optic nerve head (ONH) blood flow during moderate increases in intraocular pressure (IOP) in patients with primary open-angle glaucoma (POAG) and normal controls.

Design: Two nonrandomized studies comparing blood flow responses in glaucoma patients and controls in an open design.

Effect of nimodipine on ocular blood flow and colour contrast sensitivity in patients with normal tension glaucoma.

Aim: To investigate the effects of oral nimodipine on ocular haemodynamic parameters and colour contrast sensitivity in patients with normal tension glaucoma (NTG).

Design: The study was performed in a randomised, placebo controlled, double masked, crossover design.

Participants: Nimodipine (60 mg) or placebo was administered to 14 consecutive NTG patients.

Effect of laser photocoagulation on the retinal vessel diameter in branch and macular vein occlusion.

Objective: To investigate the response of retinal vessel diameters to photocoagulation treatment and their role for the success of laser treatment in patients with retinal vein occlusion.

Methods: The study included 14 patients with branch vein occlusion or macular vein occlusion. The ophthalmologic examination included best-corrected visual acuity, biomicroscopy, fundus photography, and fluorescein angiography.

Twelve hour reproducibility of choroidal blood flow parameters in healthy subjects.

Aims/background: To investigate the reproducibility and potential diurnal variation of choroidal blood flow parameters in healthy subjects over a period of 12 hours.

Methods: The choroidal blood flow parameters of 16 healthy non-smoking subjects were measured at five time points during the day (8:00, 11:00, 14:00, 17:00, and 20:00). Outcome parameters were pulsatile ocular blood flow as assessed by pneumotonometry, fundus pulsation amplitude as assessed by laser interferometry, blood velocities in the opthalmic and posterior ciliary arteries as assessed by colour Doppler imaging, and choroidal blood flow, volume, and velocity as assessed by fundus camera based laser Doppler flowmetry.