Background/Aim. In this study we compared the two groups of glaucoma patients who had underwent trabeculectomy, with or without intraoperative application of antimetabolite 5-Fluorouracile (5 FU). Methods. We followed up 50 glaucoma patients (group I) in a four-years period after trabeculectomy alone (antimetabolites were not applied), and 50 patients in whom antimetabolite 5 FU was applied (group II). We followed up intraocular pressure (IOP), visual acuity (VA), lens transparency, optic disc changes, visual fields (VF perimetry).The IOP at the time of the surgery, and the period of the treatment before the surgery were the important data for the follow-up. Results. The results that we got in the first group were: in 8 patients (16%) there was no change of VA, and of optic disc with a mild VF deterioration; in 18 patients (33%) the worsening of VA by 1 Snellen line (3 years after the surgery) with no change of the disc and a mild VF progressing; in 10 patients (20%) VA decreased by 2 Snellen lines with the progressive VF changes and cataract appearance, (cataract and VA worsening appeared mainly 3 years after the surgery); in 6 patients (12%) by 3 Snellen lines, and in 4 patients (8%) by 4 Snellen lines. In 4 patients (8%), the highest worsening of VA - (0.2) and the best (0.9) at the time of the surgery were observed. The VA ranging from 0.4-0.6 at the time of the surgery yielded the longest preservation of vision. In the group II (5 FU applied intraoperatively): in 5 patients (10%) there was no change of VA and of optic disc with a mild VF deterioration; in 20 patients (40%) the worsening of VA by 1 Snellen line, with no change of the disc and a mild VF progressing. In 14 patients (28%) VA decreased by 2 Snellen lines with the progressive VF changes and cataract appearance; in 7 patients (14%) by 3 Snellen lines, and in 4 patients (8%) by 4 Snellen lines. Conclusion. All of the checked parameters were better in the group II of the patients, (5 FU applied intraoperatively). Also, in the group of the patients with the longest treatment before the surgery and with the good VA, and in the patients with the shorter treatment and with the bad VA, the quickest progression of the vision lost was observed. The best preservation of VA was recordered in the patients with a mild IOP, and in those who had not been treated more than 1 or 2 years with the drops before the surgery. The VA ranging from 0.4-0.6 at the time of the surgery allowed the longest preservation of vision.