The investigators are studying motivational interviewing (MI). MI is a counseling method to help people adopt healthy behaviors. The investigators will test whether MI improves patients' accurate use of glaucoma eye drops. The investigators will train eye clinic staff called glaucoma educators to use MI. Up to 250 patients at 3 clinics will be recruited. All patients will receive their usual eye care. Based on chance, some patients will also be supported by a glaucoma educator. The groups will be compared on medication adherence using micro-electro-mechanical system(MEMS). MEMS are electronic bottle caps that track when a medication bottle is opened. Patients will be aware that their medication use is tracked. The groups will also be compared on treatment value, outcomes, and cost. The investigators will also collect data on variables that may predict medication adherence.

Inclusion Criteria:

• community-dwelling adults with primary or secondary open-angle glaucoma, and
• a current prescription for monotherapy topical glaucoma medication.

Exclusion Criteria:

• patient-reported inability to administer eye drops that cannot be addressed successfully through in-person instruction at the clinic,
• cognitive impairment at a level that would in the judgment of the referring physician interfere with study participation,
• referring physician's determination that glaucoma surgery is likely within the next 6 months,
• any active medical, psychological, or substance use disorder that would in the referring physician's judgment significantly interfere with study participation (e.g., comorbid congestive heart failure (CHF) resulting in a recent hospitalization; active psychosis due to uncontrolled bipolar disorder; etc.), or
• no visual field test within the past 6 months (data required for the randomization approach described below).