PURPOSE: To test the association between use of calcium channel blocker (CCB) medications and the rate of visual field (VF) progression in a large cohort of patients from five glaucoma clinics. DESIGN: Retrospective, longitudinal case-control study. SUBJECTS: Patients attending five glaucoma clinics in the United Kingdom using the same Electronic Medical Record (EMR) system. METHODS: For the main analysis, we selected one eye of patients with at least 5 reliable (false positive errors <
15%) VFs over at least 4 years. The use of systemic medications was derived from the EMR system. CCB users were identified as cases. Propensity Score Matching (PMS) and multivariable analyses (MV) were used to adjust for confounders. A Directed Acyclic Graph (DAG) of the relevant variables guided the selection of covariates. Linear mixed effect models (LMMs) were used to test the effect on the rate of VF Mean Deviation (MD) associated with CCB use and other covariates (for the MV analysis). Sensitivity analyses were conducted with different inclusion criteria and cut-offs on the estimated duration of CCB use. MAIN OUTCOME MEASURE: Mean difference in the rate of VF MD progression between CCB users and controls. RESULTS: The main analysis included 14,475 eyes (1,942 from CCB users) which met the selection criteria (one eye per patient). The Median [Interquartile Range] VF series length was 8 [6, 11] tests, with a follow-up of 8.6 [6, 11.5] and 8.2 [5.9, 11.2] years in CCB users and controls respectively. One-to-one PSM pairing with controls was achieved for all CCB users. The estimated rate of MD progression was -0.31 [-0.33, -0.28] dB/year (Mean [95%-Confidence Intervals]) in the CCB users and -0.35 [-0.37, -0.33] dB/year in the matched controls (p = 0.016). This significant difference was confirmed with the MV analysis, including all controls (p = 0.020). All sensitivity analyses confirmed the main results. CONCLUSIONS: CCB use was statistically significantly associated with a slower rate of VF deterioration, after multivariable adjustment. The estimated difference was small and likely not clinically significant but may be influenced by the limited information on the duration of CCB exposure in this cohort.