OBJECTIVES: To describe the patterns and the economics of glaucoma treatment. METHODS: Ophthalmologists selected at random had to include 4 consecutive patients older than 18 seen in consultation during a week, 2 with glaucoma and 2 with ocular hypertension (OH). Socio-demographics, general and eye comorbidities, glaucoma risk factors, clinical data, and medical item consumption over the previous 5 years were collected. The economic perspective was society's. Predictive medical factors of costs were identified using a stepwise regression. RESULTS: 84 ophthalmologists included 337 patients who were 60% female with a mean age of 62; 34.1% had OH and 35.9% were still receiving first line treatment. Glaucoma patients were older and no difference was found on confounding factors. Patients with glaucoma visited practitioners more often (+0.74 / year), had more exams (0.42), and were more likely to be using drug combinations (+28.5%) and to be hospitalised (+16.2%). Drugs represented the bulk of the expenses followed by exams and office visits. Two main clinical factors contributed to costs: abnormalities of the papilla due to the presence of glaucoma (+ EURO 96.43) and the number of treatment switches (+ EURO 127.62 / switch). These were followed by IOP (+ EURO 7.08 / mm Hg) and VA (+ EURO 41.37 / 2 Lines lost VA). In comparison to work conducted in the mid-nineties, drug costs increased while hospital costs decreased, although methodologies were different. CONCLUSION: Two independent factors explained the bulk of total cost variance: the presence of glaucoma and therapy switches. They contributed independently in an additive way to total cost. Under isotropic hypotheses, effective early treatment strategies aimed at postponing the effects of glaucoma and controlling IOP are expected to be cost saving in the long-term.