Ninety patients with medically uncontrollable glaucomas and poor surgical prognoses received single-plate Molteno implants (Optomat Supplies, Dunedin, New Zealand) without postoperative adjunctive systemic antifibrosis therapy. Eleven patients had insufficient follow-up for assessment of intraocular pressure (IOP) or visual acuity outcome. The initial Molteno implant procedures in the remaining 79 patients were successful (IOP less than or equal to 21 mmHg with at least 6 months' follow-up) in 26 (63%) of the 41 patients older than 12 years of age with non-neovascular glaucomas in aphakia/pseudophakia; 7 (70%) of the 10 patients older than 12 years of age with non-neovascular glaucomas in phakic eyes after failed filtering surgery; 7 (47%) of the 15 patients with neovascular glaucomas; and 7 (54%) of the 13 patients younger than 13 years of age with non-neovascular glaucomas. The visual acuities remained within one line of their preoperative levels or improved in 31 (76%) of the 41 aphakic or pseudophakic eyes with non-neovascular glaucomas; 3 (30%) of the 10 phakic eyes with non-neovascular glaucomas after failed filtering surgery; 10 (67%) of the 15 eyes with neovascular glaucomas; and 9 (100%) of the 9 eyes with non-neovascular glaucomas in patients younger than 13 years of age on whom Snellen acuity was available.(ABSTRACT TRUNCATED AT 250 WORDS)