AIM:To evaluate the outcomes of trabeculectomy with large area mitomycin-C (MMC) application as a first line treatment in advanced glaucoma.METHODS:The records of 55 patients with severe visual field defects undergoing trabeculectomy were retrospectively reviewed. The patients were classified as first-line therapy to either early trabeculectomy (initial trabeculectomy-Group 1) or long term medical therapy followed by trabeculectomy (primary trabeculectomy-Group 2). Trabeculectomy was performed with large-area MMC application. Intraocular pressure (IOP) values, visual acuities, mean deviations, morphology and function of the blebs, necessity for anti-glaucomatous medications and surgical complications were reported.RESULTS:There were 20 eyes of 18 patients in Group 1 and 37 eyes of 37 patients in Group 2. The mean preoperative IOPs in Groups 1 and 2 were 40.2±10.0mmHg (27-68mmHg) and 29.0±4.4mmHg (21-41mmHg), respectively (P=0.001). Average preoperative mean deviations (MD) in Groups 1 and 2 were 17.4±2.8dB (13.3-23dB) and 17.9±2.4 dB (13.7-23.2dB), respectively (P=0.441). Postoperative IOPs significantly decreased and were comparable in both Groups. The mean number of medications was significantly higher in Group 2 (P=0.005). No cystic bleb formation was observed in Group 1, whereas 4 patients from Group 2 (10.8 %) developed cystic bleb (P=0.040). No visually devastating complication has occurred in both Groups.CONCLUSION:Initial trabeculectomy with large area MMC application might be applied in patients with advanced glaucoma with low complication rates. Long-term topically applied anti-glaucomatous medications seem to increase the risk of cystic bleb formation.