External Influences Upon Ocular Homeostasis

Purpose

Our experiments are designed to test the overall hypothesis that position-dependent or water-dependent intra-ocular pressure (IOP) spikes occur in humans, and that these challenge ocular homeostasis.

Condition

  • Intraocular Pressure

Eligibility

Eligible Ages
Between 10 Years and 90 Years
Eligible Genders
All
Accepts Healthy Volunteers
Yes

Inclusion Criteria

  • Patients with autonomic dysfunction
  • Patients with open-angle glaucoma
  • Patients with normal-pressure glaucoma
  • Normal subjects

Exclusion Criteria

  • Medical students
  • Prisoners
  • Pregnant women

Study Design

Phase
N/A
Study Type
Interventional
Allocation
Non-Randomized
Intervention Model
Parallel Assignment
Primary Purpose
Basic Science
Masking
None (Open Label)

Arm Groups

ArmDescriptionAssigned Intervention
Experimental
Subjects with autonomic dysfunction
Subjects with known autonomic dysfunction diagnoses as defined by the General Clinical Research Center (GCRC) such as pure autonomic failure, Postural orthostatic tachycardia syndrome (POTS), and Multiple System Atrophy( MSA). Intraocular pressures, blood pressures, and retinal thicknesses are measured with postural changes Intraocular pressures, blood pressures, and retinal thicknesses are measured with water drinking.
  • Behavioral: Postural change
    Intraocular pressures, blood pressures, and retinal thicknesses are measured with postural changes
  • Behavioral: Water drinking
    Intraocular pressures, blood pressures, and retinal thicknesses are measured with water drinking.
Experimental
Primary open-angle glaucoma subjects
Subjects diagnosed with primary open-angle glaucoma following a glaucoma specialist's examination. Intraocular pressures, blood pressures, and retinal thicknesses are measured with postural changes Intraocular pressures, blood pressures, and retinal thicknesses are measured with water drinking.
  • Behavioral: Postural change
    Intraocular pressures, blood pressures, and retinal thicknesses are measured with postural changes
  • Behavioral: Water drinking
    Intraocular pressures, blood pressures, and retinal thicknesses are measured with water drinking.
Experimental
Subjects with normal-pressure glaucoma
Subjects with open-angle glaucoma damage following a glaucoma specialist's examination without ever an intraocular pressure recording greater than 21 mm Hg. .1. Intraocular pressures, blood pressures, and retinal thicknesses are measured with postural changes 2. Intraocular pressures, blood pressures, and retinal thicknesses are measured with water drinking.
  • Behavioral: Postural change
    Intraocular pressures, blood pressures, and retinal thicknesses are measured with postural changes
  • Behavioral: Water drinking
    Intraocular pressures, blood pressures, and retinal thicknesses are measured with water drinking.
Active Comparator
Normal subjects
Subjects without evidence of glaucoma or autonomic dysfunction. ..1. Intraocular pressures, blood pressures, and retinal thicknesses are measured with postural changes 2. Intraocular pressures, blood pressures, and retinal thicknesses are measured with water drinking.
  • Behavioral: Postural change
    Intraocular pressures, blood pressures, and retinal thicknesses are measured with postural changes
  • Behavioral: Water drinking
    Intraocular pressures, blood pressures, and retinal thicknesses are measured with water drinking.

Recruiting Locations

Vanderbilt University
Nashville, Tennessee 37232
Contact:
Scott Ruark
615-936-1639
scott.ruark@vanderbilt.edu

More Details

NCT ID
NCT00338065
Status
Recruiting
Sponsor
Vanderbilt University Medical Center

Study Contact

Karen Joos, MD, PhD
615-936-1957

Detailed Description

Glaucoma is the second leading cause of blindness in the United States, yet its pathogenesis is poorly understood. This is an insidious disorder since the loss of peripheral vision which occurs first usually is not noticed by the victim. Approximately 1 million people in the United States have glaucoma, but are not aware of it. Glaucoma is not always associated with elevated intraocular pressures so that vision screenings which measure just intraocular pressure without assessing the optic nerve will also miss these patients with glaucomatous damage. Therefore, patients are often diagnosed only when they have severe irreversible vision loss. Vascular insufficiency or abnormal autoregulation versus mechanical pressure damage has been proposed as a major factor in the development of glaucoma. Presently, therapy is based upon lowering intraocular pressure. If a contributing intermittent pressure elevation factor can be elucidated and characterized, specific treatment modalities may then be developed and their effectiveness can be monitored.