PURPOSE To explore the effects of brief intravenous (IV) infusion of vascular endothelial growth factor (VEGF) on vascular albumin permeability, blood flow, and vascular conductance (blood flow normalized to arterial blood pressure) in ocular tissues and brain and to assess the role of nitric oxide in mediating these changes. METHODS A quantitative, double-tracer, radiolabeled albumin permeat...

The effect of segmental scleral buckling (SB) on ocular circulation was evaluated by measurements of the ocular pulse amplitude (PA) and the ophthalmic artery pressure (OAP). In this study the OAP was defined as the intraocular pressure (IOP) at which the PA disappeared during increasing IOP. Twenty four patients with unilateral rhegmatogenous retinal detachment who underwent SB of varying exte...

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. Methods: The effects or oral nimodipi...

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. METHODS The effects or oral nimodi...

PURPOSE Clonidine and brimonidine, two alpha-2 agonists, have been shown to reduce intraocular pressure (IOP) in patients with glaucoma. Little is known, however, about the exact role of alpha receptors in the control of ocular blood flow in the posterior pole of the eye. Hence, the study was conducted to investigate the effects of topical clonidine versus topical brimonidine on choroidal blood...

AIM In the present study the response of optic nerve head blood flow to an increase in ocular perfusion pressure during isometric exercise was studied. Based on our previous studies we hypothesized that subjects with an abnormal blood flow response, defined as a decrease in blood flow of more than 10% during or after isometric exercise, could be identified. METHODS A total of 40 healthy subje...

Rapid, short-lasting elevation of ocular pressure level produces simultaneous reduction in blood-flow rate in the distal 6 mm. of the extraocular portion of the optic nerve of the rhesus monkey as monitored by the heated thermocouple technique. The magnitude of this reduction was very small until intraocular pressure (IOP) exceeded 50 mm. Hg following which markedly and progressively greater re...