Objective To investigate the effect of a patient decision aid applied in persons having primary open-angle glaucoma (POAG). Methods One hundred POAG patients were chronologically assigned to two groups, with 50 in each. The control group was given routine nursing care, while the observation group additionally received decision-making assistance. The effects were measured immediately post intervention (before discharge) and at 1 and 3 months post discharge. Results The observation group had significantly lower score of decisional conflict but higher score of preparation for decision-making compared with the control group after the intervention (both P<0.05). The scores of medication adherence at 1 and 3 months post discharge, as well as the achieving rate of target intraocular pressure at 3 months post discharge were significantly higher in the observation group than those in the control group (all P<0.05). Conclusion The patient decision aid formulated in this study can effectively reduce decisional conflict of patients, improve their preparation for decision-making, enhance medication adherence, and increase the achieving rate of target intraocular pressure.