A randomized, prospective study was undertaken to compare the results of the double-plate Molteno implant with those of the anterior chamber tube shunt to encircling band (ACTSEB) procedure, described by Schocket, for eyes with complicated glaucoma. One surgeon performed all the procedures. For statistical analysis there were 21 eyes in the ACTSEB group and 19 eyes in the Molteno group, with at least 6 months of follow-up (mean follow-up, 26 months; range, 6 to 49 months). Eyes with aphakia/pseudophakia, uveitis, previous penetrating keratoplasty, previous unsuccessful trabeculectomy, and neovascular glaucoma were evenly distributed between the two groups. Mean preoperative intraocular pressures in the ACTSEB and Molteno groups were 35.2 and 34.6 mm Hg, respectively. With the exclusion of one phthisical eye in each group final mean intraocular pressure in the ACTSEB group was 15.1 mm Hg, with a mean of 0.43 medications, and 14.4 mm Hg, with a mean of 0.95 medications, in the Molteno group. Seven (33%) of 21 eyes and 13 (68%) of 19 eyes in the ACTSEB and Molteno groups, respectively, were receiving additional antiglaucoma medication at the most recent visit (P = .027). Final visual acuity was stable (within one Snellen line of baseline visual acuity) or improved in 10 (48%) of 21 eyes in the ACTSEB group compared with 13 (68%) of 19 eyes in the Molteno group. Complications or inadequate pressure control requiring further surgical intervention were seen in nine (47%) of 19 eyes in the Molteno group and 12 (57%) of 21 eyes in the ACTSEB group.(ABSTRACT TRUNCATED AT 250 WORDS)