Choroidal Thickness During Changes in Intraocular Pressure and Arterial Blood Pressure

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.

Study Overview

• Status: Terminated
• Conditions: Healthy
• Intervention / Treatment: Drug: Phenylephrine; Drug: Sodium-Nitroprusside; Device: Suction Cup; Device: Goldmann applanation tonometer; Device: 1060nm Optical coherence tomography

• Study Type: Interventional
• Enrollment (Actual): 1
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Austria
  • Vienna, Austria, 1090
    • Department of Clinical Pharmacology, Medical University of Vienna

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 35 years (Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Men and women aged between 18 and 35 years, nonsmokers
• Men and women will be included in equal parts
• Normal findings in the medical history and physical examination unless the investigator considers an abnormality to be clinically irrelevant
• Normal findings in the laboratory testings unless the investigator considers an abnormality to be clinically irrelevant
• Normal ophthalmic findings, ametropia less than 1 diopter

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 (except oral contraceptives)
• Symptoms of a clinically relevant illness in the 3 weeks before the first study day
• Blood donation during the previous 3 weeks History of hypersensitivity to the trial drugs 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
• Pregnancy

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Triple

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: 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	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
Active Comparator: 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: 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
Active Comparator: Suction Cup; suction force of 25, 50, 75, and 100 mmHg	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

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Choroidal thickness	18 months

Secondary Outcome Measures

Outcome Measure	Time Frame
Systolic/diastolic blood pressure (non-invasive)	18 months
Intraocular pressure (IOP)	18 months

Collaborators and Investigators

• Sponsor: Medical University of Vienna
• Investigators: Principal Investigator: Gerhard Garhöfer, MD, PD, Department of Clinical Pharmacology, Medical University of Vienna

Study record dates

Study Major Dates

• Study Start: December 1, 2012
• Primary Completion (Actual): December 1, 2012

Study Registration Dates

• First Submitted: April 11, 2011
• First Submitted That Met QC Criteria: April 11, 2011
• First Posted (Estimate): April 12, 2011

Study Record Updates

• Last Update Posted (Estimate): November 14, 2014
• Last Update Submitted That Met QC Criteria: November 13, 2014
• Last Verified: November 1, 2014

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Physiological Effects of Drugs; Adrenergic Agents; Neurotransmitter Agents; Molecular Mechanisms of Pharmacological Action; Antihypertensive Agents; Vasodilator Agents; Autonomic Agents; Peripheral Nervous System Agents; Protective Agents; Adrenergic alpha-Agonists; Adrenergic Agonists; Cardiotonic Agents; Respiratory System Agents; Sympathomimetics; Vasoconstrictor Agents; Mydriatics; Nitric Oxide Donors; Nasal Decongestants; Adrenergic alpha-1 Receptor Agonists; Phenylephrine; Oxymetazoline; Nitroprusside
• Other Study ID Numbers: OPHT-151010