Aqueous Humor Dynamics and Brimonidine

This single-center, investigator-masked, crossover study is designed to investigate the
circadian rhythms of aqueous humor dynamics in human subjects with ocular hypertension (OHT)
before and after intervention with a commonly used ocular hypotensive medication,
brimonidine. Thirty volunteers with ocular hypertension (intraocular pressure greater than
20mmHg) will be enrolled.

The subjects will undergo a baseline phase and medication phase using brimonidine. At both
phases, they will attend a daytime and a nighttime study visit in which fluorophotometry will
be used to calculate aqueous flow (production), trabecular outflow facility, and uveoscleral
outflow. At the completion of the study, subjects will return to their previous ophthalmic
clinic.

Inclusion Criteria:

- Subjects must be 19 years of age or older

- Subjects must exhibit a history of untreated IOPs between 21 and 35 mmHg (inclusive)

Exclusion Criteria:

- Age less than nineteen years old

- Women who are pregnant, lactating or of childbearing potential who are not using birth
control measures.

- Aphakia or pseudophakia

- Best corrected visual acuity worse than 20/60 in either eye

- Chronic or recurrent severe ocular inflammatory disease

- Ocular infection or inflammation within (3) months of screening visit.

- History of clinically significant or progressive retinal disease such as retinal
degeneration, diabetic retinopathy or retinal detachment.

- Any abnormality preventing reliable tonometry of either eye.

- Previous exposure to: beta-adrenergic antagonists, topical prostaglandin analogues
within six (6) weeks of the baseline visit; α-adrenergic agonists within two (2) weeks
of the baseline visit; and cholinergic agonists and carbonic anhydrase inhibitors
within five (5) days of the treatment initiation visit.

- History of any severe ocular pathology (including severe dry eye) that would prelude
the administration of a topical beta blocker, carbonic anhydrase inhibitor, or a
topical prostaglandin.

- Any eye with a cup-to-disc ratio greater than 0.8.

- History of intraocular surgery

- History of ocular laser surgery

- History of severe or serious hypersensitivity to brimonidine or its vehicle.

- History of severe, unstable, or uncontrolled cardiovascular, hepatic or renal disease.

- History of bronchial asthma or chronic obstructive pulmonary disease (COPD).

- Less than one month (prior to baseline) stable dosing regimen of any non-glaucoma
medication that would affect IOP.

- Gonioscopy angle < 2.

- Inability to be dosed with treatment medication

- Inability to discontinue contact lens wear.

- Therapy with any investigational agent within 30 days of screening.

- Use of any additional topical or systemic adjunctive ocular hypotensive medications
during the study.

- History of open angle glaucoma (either primary open angle glaucoma or other cause of
open angle glaucoma) or narrow angle glaucoma.