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.

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.

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