After the investigators performed the filtering surgery and determined that the new outlet channel was working, patients were randomized to receive either 5-FU injections or standard postsurgical care without 5-FU. The patients treated with 5-FU received subconjunctival injections of 5 mg of 5-FU twice daily on postoperative days 1 through 7 and once daily on postoperative days 8 through 14. There were 213 patients recruited into the study, 162 with previous cataract extraction and 51 with previous filtering surgery.