The purpose of this study is to evaluate the safety, efficacy, and usability of an eyedrop bottle adaptor that creates smaller eyedrops, Nanodropper, in an open-angle glaucoma/ocular hypertension patient population.

This 6-month prospective, randomized, single-masked, active-controlled, crossover (AB:BA) study aims to evaluate the safety, efficacy, and usability of Nanodropper-mediated microdrops of IOP-lowering medications (experimental intervention) compared to standard eyedrops of the same medications (active comparator) in open-angle glaucoma or ocular hypertension patients at Harborview Eye Institute, for which permission has been obtained. A pre-study visit will be held before the start of the trial in which participant clinical histories will be documented and an ocular examination will be performed. Patients will be enrolled in the study by satisfying all the inclusion and none of the exclusion criteria. This 6-month study will include three clinic visits: a baseline visit at t = 0, crossover visit at t = 3 months, and final visit at t = 6 months. At the baseline visit, patients will be randomly assigned to one of two treatment groups (1:1): Group 1 will administer standard eyedrops everyday for three months before crossing over to administering Nanodropper-mediated microdrops daily for three months and Group 2 will administer Nanodropper-mediated microdrops everyday for three months before crossing over to administering standard eyedrops daily for three months. At the visit that precedes the onset of the standard eyedrops treatment period, subjects will receive education on how to properly instill eyedrops. At the visit that precedes the onset of the Nanodropper treatment period, patients will receive education on how to properly instill eyedrops with the Nanodropper as well as one Nanodropper per bottle of prescription eyedrops. Patients will be instructed to use the Nanodropper with their bottle of eyedrops until the bottle is nearly depleted and they are due for a refill. Because the Nanodropper isn't reusable, subjects will be instructed to contact the clinic for additional Nanodroppers at the time that they refill their prescriptions. At each clinic visit, the IOP of each eye will be measured at 8 AM, 10 AM, and 12 PM using a calibrated Goldmann applanation tonometer by a masked evaluator. Additionally, surveys designed to assess whether Nanodropper impacts the financial burden and side effect profiles associated with chronic eyedrop use, as well as the usability of Nanodropper compared to standard eyedrop bottles, will be administered.

Inclusion Criteria:

• ≥18 years old
• Primary open-angle glaucoma (OAG) diagnosis
• Ocular hypertension (OHT) diagnosis
• Corneal thickness <600 µm
• Use 1-2 IOP-lowering eyedrop medications that are compatible with Nanodropper
• OAG/OHT must be well-controlled (defined as ≥2 IOP measurements collected within 6 months of recruitment that are ≤21 mm Hg with variability of ±3 mm Hg)
• OAG/OHT must be progression-free (as judged by the clinician and based on ≥2 stable OCT and visual field tests collected in the 6 months prior to recruitment)

Exclusion Criteria:

• Uncontrolled glaucoma (IOP >21 mmHg)
• Use of >2 medications for treatment of OAG/OHT
• Use of eyedrop medications that are incompatible with Nanodropper
• OAG/OHT progression (as judged by the clinician within the past 6 months)
• Eye surgery including laser procedures (e.g., SLT, iridotomy) within 6 months of recruitment
• Diagnosis of acute angle-closure glaucoma and/or other retinal diseases

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