Predictors for visual field progression and the effects of treatment with dorzolamide 2% or brinzolamide 1% each added to timolol 0.5% in primary open‐angle glaucoma

Purpose: This study aims to identify progression factors in patients with primary open‐angle glaucoma (POAG), including the effects of treatment with dorzolamide 2% or brinzolamide 1%, each added to timolol 0.5%. Methods: A sample of 161 POAG patients were prospectively randomized to receive either dorzolamide 2% (DT) or brinzolamide 1% (BT) b.i.d., each added to timolol 0.5%, during a 60‐month, evaluator‐masked study. Progression was determined by perimetric criteria. Factors associated with visual field progression were estimated using a conditional Cox hazard model with patient intraclass correlation and were expressed as hazard ratios (HRs) with 95% confidence intervals (95% CIs). Results: Predictive baseline factors were lower diastolic blood pressure (DBP), lower mean arterial pressure (MAP), antihypertensive treatment, lower end‐diastolic velocity (EDV) in the ophthalmic artery (OA) and short posterior ciliary artery (SPCA), and a higher resistivity index (RI) in the OA and SPCA. Progression risk decreased by approximately 30% and 20% with each centimetre per second increase of EDV in the OA and SPCA, respectively, from baseline to the last follow‐up visit. Each RI decrease (or increase) of 0.01 unit in the OA or SPCA was associated with an approximate 20% decrease (or increase) in risk for progression. In a multivariate analysis, progression risk was significantly lower in eyes treated with DT (HR = 0.65, 95% CI 0.41–0.90) compared with those treated with BT. Conclusions: Progression increased with lower DBP, lower MAP, antihypertensive medication, lower EDV in the OA and SPCA, and higher RI in the OA and SPCA. The risk for progression in patients treated with DT was half that in patients treated with BT.