External Influences Upon Ocular Homeostasis

Vanderbilt University Medical Center

Status: Invitation-only

Conditions: Intraocular Pressure

Treatments: Behavioral: Water drinking; Behavioral: Postural change

Study type: Interventional

Funder types: Other

Identifiers

NCT00338065

Vanderbilt IRB# 010436

Details and patient eligibility

About

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.

Full 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.

Enrollment: 200 estimated patients

Sex: All

Ages: 10 to 90 years old

Volunteers: Accepts Healthy Volunteers

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

Trial design

Primary purpose: Basic Science

Allocation: Non-Randomized

Interventional model: Parallel Assignment

Masking: None (Open label)

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200 participants in 4 patient groups

Subjects with autonomic dysfunction

Experimental group

Description:

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). 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.

Treatment:

Behavioral: Postural change

Behavioral: Water drinking

Primary open-angle glaucoma subjects

Experimental group

Description:

Subjects diagnosed with primary open-angle glaucoma following a glaucoma specialist's examination. 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.

Treatment:

Behavioral: Postural change

Behavioral: Water drinking

Subjects with normal-pressure glaucoma

Experimental group

Description:

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.

Treatment:

Behavioral: Postural change

Behavioral: Water drinking

Normal subjects

Active Comparator group

Description:

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.

Treatment:

Behavioral: Postural change

Behavioral: Water drinking