Persistence of Glaucoma Therapy and Visual Field Progression.

PURPOSE: To determine the association of visual field (VF) progression with medication persistence in a cohort on glaucoma therapy.

PATIENTS AND METHODS: Pharmacy records were examined over 3 years for patients started on glaucoma monotherapy. A patient was persistent if a prescription was refilled for the same medication < 90 days after the previous prescription had lapsed; otherwise was nonpersistent. Only patients with > 5 reliable VFs within 1-year pretherapy and 6-year posttherapy were included. Progression was analyzed with pointwise linear regression and defined using 2 criteria: (A) ≥ 2 adjacent progressing points (slope P < 0.01) in 1 hemifield; and (B) ≥ 3 progressing points (slope P < 0.01). The mean number and mean slope of progressing points and the mean global slopes were determined.

RESULTS: Of 1206 patient eyes (131 persistent, 1075 nonpersistent), 941 were excluded leaving 175 (47 persistent and 128 nonpersistent) for analysis. The mean follow-up durations were 59.3 ± 10.9 and 58.2 ± 9.7 months (P = 0.07) for persistent and nonpersistent eyes, respectively. Overall, 2/47 (4.3%) and 10/128 (7.8%) eyes progressed among persistent and nonpersistent patients, respectively (P = 0.52) using criterion A and 1/47 (2.1%) and 12/128 (9.4%; P = 0.19) eyes using criterion B. Mean number of progressing points (0.3 ± 0.9 vs. 0.7 ± 1.8; P = 0.17), mean slope of progressing points (-2.2 ± 1.1 vs. -2.8 ± 1.3 dB/y; P = 0.27), and mean global slope (0.7 ± 0.5 vs. -0.1 ± 0.8 dB/y; P = 0.07) were similar for persistent and nonpersistent patients, respectively.

CONCLUSION: There were small but appreciable differences in VF progression rates between persistent and nonpersistent patient eyes on glaucoma drops, but differences were not significant.