AIM: To assess physical activity (PA) including its intensity in primary open angle glaucoma (POAG). METHODS: PA was characterized by the use of questionnaires: Seven-Day Physical Activity Recall and Historical Leisure Activity Questionnaire. A questionnaire of 36 questions, developed by the authors, was used to assess the level of knowledge about glaucoma RESULTS: The study was conducted among 625 adults. The study group comprised 312 POAG patients aged over 40y, including 238 women (76%) and 74 men (24%). The control group consisted of 313 adults (>40 years old), including 202 (65%) women and 111 men (35%). The duration of current PA with an intensity of 4 metabolic equivalents (METs) was significantly shorter among people with POAG. PA in the past was significantly lower among people from the study group, regardless of gender. The level of glaucoma knowledge in patients with POAG was poor and significantly lower in men. CONCLUSION: Regular PA is an important and underestimated factor predisposing to the progression of POAG. There is a necessity to undertake educational and preventive actions with a view to modify the health behavior of glaucoma patients.