PURPOSE: To analyze the results of 87 consecutive one-stage Molteno implantations in 87 patients and evaluate the factors influencing the surgical outcome, especially the effect of intraoperative partial and total occlusion of the tube. METHODS: Successful outcome was defined as final intraocular pressure (IOP) between 6 and 22 mmHg with less or equal amount of glaucoma medication than preoperatively without loss of light perception. RESULTS: After a mean (+/-SD) follow-up of 24+/-17 months, the mean IOP was 18.1+/-16.0 mmHg compared to the preoperative mean of 42.4+/-11.1 mmHg (p