Study to Assess the Efficacy, Safety and Tolerability of AKB-9778 Ophthalmic Solution as and Adjunct to Latanoprost in Patients With Ocular Hypertension or Open Angle Glaucoma

Key Inclusion Criteria: * Diagnosis of OAG or OHT in each eye (OAG in one eye and OHT in the fellow eye is acceptable) * Must be receiving treatment with a stable regimen of topical prostaglandin eyedrop for a minimum of 2 weeks prior to the Screening Visit; may be taking one additional IOP lowering eyedrop * IOP of ≥ 18 mmHg and ≤ 27 mmHg in one eye or both eyes at Screening visit * Following 4 week washout period, IOP ≥ 24 mmHg and \< 36 mmHg at 08:00 hour and IOP ≥ 22 mmHg and \< 36 mmHg in both eyes at 10:00, 12:00 and 16:00 hours. Key Exclusion Criteria: * Clinically significant ocular disease which might interfere with interpretation of the study efficacy endpoints or with safety assessments * Pseudoexfoliation or pigment dispersion component glaucoma * History of angle closure glaucoma, or narrow angles or with evidence of peripheral anterior synechiae (PAS) ≥ 180 degrees by gonioscopy within 6 months prior to Screening * Intraocular pressure ≥ 36 mmHg * Cup/disc ratio of \> 0.8 in either eye * Severe visual field defect or significant defect (sensitivity of ≤ 10dB) within 10 degrees of fixation in either eye