Ocular Hemodynamic Effects of Nitrovasodilators in Healthy Subjects

Medical University of Vienna14 enrolled

Overview

Glaucoma, one of the most common causes of blindness, is associated with increased intraocular pressure (IOP) and optic nerve head ischemia. Nitrovasodilators are discussed in the treatment of glaucoma. Nitrates relax smooth muscle cells in the vasculature by liberating the vasodilator nitric oxide. The IOP lowering potential and the vasodilator action in retinal and choroidal vessels of nitrates is still a matter of controversy. Previous studies on the ocular hemodynamic effects of nitrates showed partially contradicting results. In addition the IOP lowering effect of nitrates is still unclear. However, recent studies show that long acting nitrates may preserve optic nerve deterioration and visual field loss. Therefore, the role of nitrovasodilators in control of ocular blood flow and intraocular pressure has to be elucidated. For this purpose the investigators plan to test the hypothesis that nitrovasodilators improve ocular blood supply to the optic nerve head at doses which do not affect systemic hemodynamics.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

TRIPLE

Enrollment

Conditions

Glaucoma

Interventions

Eligibility

Sex: MALEMin age: 19 YearsMax age: 35 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: * Men aged between 19 and 35 years, nonsmokers * Body mass index between 15th and 85th percentile (Must et al. 1991) * Normal findings in the medical history and physical examination unless the investigator considers an abnormality to be clinically irrelevant * Normal laboratory values unless the investigator considers an abnormality to be clinically irrelevant * Normal ophthalmic findings, ametropia \< 3 Dpt. Exclusion Criteria: * Regular use of medication, abuse of alcoholic beverages, participation in a clinical trial in the 3 weeks preceding the study * Treatment in the previous 3 weeks with any drug * Symptoms of a clinically relevant illness in the 3 weeks before the first study day * History of hypersensitivity to the trial drug or to drugs with a similar chemical structure * History or presence of gastrointestinal, liver or kidney disease, or other conditions known to interfere with, distribution, metabolism or excretion of study drugs * History of migraine * Blood donation during the previous 3 weeks

Outcomes

Primary Outcomes

Optic disc blood flow (laser Doppler flowmetry)

Time frame: in total 24x on 4 study days

Secondary Outcomes

Intraocular pressure

Time frame: in total 8x in 4 study days

Choroidal blood flow (laser Doppler flowmetry)

Time frame: in total 24x on 4 study days

Fundus pulsation amplitude in the macula (laser interferometry)

Time frame: in total 24x on 4 study days

Fundus pulsation amplitude in the optic disc (laser interferometry)

Time frame: in total 24x on 4 study days

Blood pressure, pulse rate

Time frame: on 4 study days

Ocular Hemodynamic Effects of Nitrovasodilators in Healthy Subjects

Overview

Conditions

Interventions

Eligibility

Locations (1)

Outcomes

Primary Outcomes

Secondary Outcomes