Choroidal Thickness During Changes in Intraocular Pressure and Arterial Blood Pressure

Summary

Age-related macular degeneration (AMD) and glaucoma are among the leading causes of blindness in the western world. Elevated intraocular pressure (IOP) is a well known major risk factor for glaucoma. In addition, there is growing evidence that vascular factors, including arterial hypertension and hypotension, may play a role in the pathogenesis of AMD and glaucoma. To gain more insight into these mechanisms in humans is the primary goal of the present study.

Optical coherence tomography (OCT) delivers three dimensional, volumetric reflectivity information through transparent media in vivo. Moreover, the images show a high choroidal penetration and a resolution comparable to an histologic examination when infrared light sources are used. Because of its non-invasive character, OCT provides an ideal method for diagnosis and monitoring of retinal and choroidal abnormalities.

The present study aims to investigate whether choroidal thickness is temporarily altered by changes in IOP or systemic hemodynamic parameters. IOP will be increased by the use of a suction cup technique, mean arterial blood pressure will be altered by intravenously administered Phenylephrine or Sodium-Nitroprusside.

Conditions

• Healthy

Interventions

DRUG

Phenylephrine

Neosynephrine®, Winthrop Breon Laboratories New York, NY, USA 0, 0.5, 1 and 2 μg/kg/min, each infusion step for 5 minutes, total infusion period of 20 minutes

DRUG

Sodium-Nitroprusside

Nipruss®, Sanol-Schwarz, Monheim, Germany 0, 0.5, 1 and 2 µg/kg/min, each infusion step for 5 minutes, total infusion period of 20 minutes

DEVICE

Suction Cup

experimental stepwise increase of intraocular pressure while measurement of choroidal thickness suction force of 25, 50, 75, and 100 mmH

DEVICE

Goldmann applanation tonometer

intraocular pressure measurements

DEVICE

1060nm Optical coherence tomography

Optical coherence tomography is a widely used non-invasive method to image the retina and choroid. Using a 1060nm light source coupled to a commercially available OCT system (Heidelberg Engineering, Heidelberg, Germany) allows for the measurement of choroidal thickness

Sponsors & Collaborators

• Medical University of Vienna

  lead OTHER

Principal Investigators

• Gerhard Garhöfer, MD, PD · Department of Clinical Pharmacology, Medical University of Vienna

Study Design

Allocation

RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

TRIPLE

Model

CROSSOVER

Eligibility

Min Age

18 Years

Max Age

35 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2012-12-31

Primary Completion

2012-12-31

Countries

• Austria

Study Locations