In this study, the potential impact of 11(th) version of the National Health System's Activity-Based Financing on the income of a University Hospital department was evaluated for glaucoma surgeries. The number of glaucoma surgeries in 2008 was analyzed based on the Medicalization Program of Information Systems. Using the 11(th) version of the Activity-Based Financing for Diagnosis-Related Groups (DRG), we compared the income of these surgical procedures on both an inpatient and an outpatient setting. One hundred and forty-nine patients undergoing glaucoma surgery between January and December 2008 were included, 94% of whom were treated on an outpatient basis. The lower reimbursement for outpatient surgery resulted in a loss of euro 100,000 or 64% of revenues compared to an inpatient procedure. Ambulatory glaucoma surgery is feasible but requires rigorous organization. Nonetheless, while department incomes are related to activity, ambulatory care seems financially disadvantageous. Many departments are trying to develop an ambulatory structure, but the apparent contradiction between the objectives of public health insurance and the hospital's need to balance its budget requires further clarification.