OBJECTIVES: Glaucoma is a condition affecting one or both eyes with raised intraocular pressure (IOP). IOP reduction can prevent or slow progression of visual field loss. The objective of the analysis was to investigate the four-year costs of bimatoprost 0.03% as an alternative to filtration surgery (FS) for glaucoma patients on maximum tolerable medical therapy (MTMT) in Italy. METHODS: A Markov model with monthly cycles based on effectiveness and resource-use data from a clinical trial and expert statements was designed. The trial covered 83 patients on MTMT. The model compared bimatoprost with FS. In one model-arm patients began treatment with bimatoprost. If a 30% reduction in IOP was not reached using mono-therapy the patient proceeded with combination-therapy and eventually FS. In the other model-arm FS was performed after the first ophthalmologist visit. In both arms treatment changes involved additional follow-up visits besides the scheduled, an increasing proportion needed pressure-lowering medication after FS and 40% were operated in both eyes. Unit costs were obtained from an Italian chart and tariffs review. The model analysed four-year costs from a national Health care sector perspective. A 5% discount rate was used. RESULTS: The 4-year cost per patient in the bimatoprost arm was €3372 with visit costs and medications contributing the most. In the FS arm four years costs were €4284 with the costs being driven by primary surgery, secondary surgery, and pressure-lowering medications needed post-surgery to control IOP. CONCLUSIONS: The analysis indicates that bimatoprost over a four year horizon is a cheaper alternative than FS. This result was strengthened by a threshold sensitivity analysis showing that the FS price would need to be reduced 73% before FS and bimatoprost were equally costly. Italian ophthalmologists should therefore consider bimatoprost as an alternative to FS.