Early Feasibility Study of the Brown Glaucoma Implant in Patients With Severe Visual Impairment or No Light Perceived

Inclusion Criteria: 1. Age 22 years and older. 2. Best corrected visual acuity of 20/400 or worse.in the study eye. 3. Fellow eye with visually acuity of 20/200 or better and the visual field no worse than the study eye. If the study eye has no light perception, the fellow eye may have no light perception or better. 4. Intraocular pressure in the study eye greater than or equal to 21 mmHg and less than or equal to 50 mmHg. 5. Primary open-angle glaucoma (confirmed by gonioscopy). 6. Glaucomatous optic nerve damage as evidenced by any of the following optic disc or retinal nerve fiber layer structural abnormalities: (1) Diffuse thinning, focal narrowing, or notching of the optic disc rim, especially at the inferior or superior poles with or without disc hemorrhage; (2) Localized abnormalities of the peripapillary retinal nerve fiber layer, especially at the inferior or superior poles; or (3) Optic disc neural rim asymmetry of the two eyes consistent with loss of neural tissue. 7. Humphrey Visual Field (HVF) demonstrating visual field defects consistent with glaucomatous optic nerve damage. 8. At least two contiguous clock hours of intact conjunctiva near the limbus between clock hours of 9:00 and 03:00 in the study eye. 9. Adequate space in the anterior chamber of the study eye sufficient to support implant with the BGI, defined as two contiguous clock hours of scleral spur visualization via goinioscopy, without compression, in the superior 180 degrees of the anterior angle. 10. Able and willing to comply with protocol requirements. 11. Able to understand and sign the Informed Consent form. Exclusion Criteria: 1. Active Neovascular Glaucoma in the study eye. 2. Pigmentary Glaucoma in the study eye. 3. Pseudoexfoliative Glaucoma in the study eye. 4. Corneal conditions in the study eye that may inhibit normal incisional healing (e.g. Fuch's dystrophy) or impair visualization of the implant inside the anterior chamber. 5. Anticipated need for ocular surgery within one year in the study eye. 6. Requirement of a combined glaucoma procedure in the study eye. 7. Contact lens use in the study eye. 8. Clinically significant inflammation or infection in the study eye within 60 days prior to the preoperative visit (e.g., blepharitis, conjunctivitis, keratitis, uveitis, herpes simplex infection) or any systemic infection. For purposes of this study, clinically significant is considered any such condition requiring prescription therapy. 9. Other clinical conditions: 1. Poorly controlled diabetes (Type I or Type II) as determined by HbA1c \>8. 2. Cancer requiring treatment during the duration of the study. 3. Any drugs (e.g.: immunosuppressive drugs) or co-morbidity that might inhibit wound healing. 10. Participation in any other clinical trial during participation in this trial. 11. Life expectancy \<1 year. If both eyes of a prospective trial participant are eligible, only the eye with the highest intraocular pressure will be selected for implant.