Measuring persistency and intraocular pressure-controlled days in patients receiving topical glaucoma medications

Investigators have developed methods to estimate the number of healthy days or symptom-free days in randomized trials or population-based settings. Such measures can be used in cost-effectiveness studies or disease management surveillance. This paper suggests that the concept can be extended to measure intraocular pressure (IOP)-controlled days in glaucoma by combining data from randomized trials on IOP control (ie, whether a target IOP or percent reduction in IOP was achieved) with data from pharmacy database studies on drug persistency. Patients with lower rates of persistency would be expected to experience fewer IOP-controlled days as they switch therapies or discontinue topical therapy altogether. Evaluating IOP-controlled days according to patients' topical glaucoma therapies could improve population-based disease management compared with the use of simpler measures that consider IOP measurements at a single point in time.