Objective:To study the efficacy of subconjunctival 5-fluorouracil(5-FU) and triamcinolone injection in halting the progression of impending recurrent pterygium.Design:Randomized,prospective,controlled clinical trial.Participants:One hundred nine patients who had undergone pterygium excision within the previous 6 months and developed grade 3 characteristics(impending recurrent pterygium) .Methods:A total of 109 eyes with impending recurrent pterygium were stratified randomly into 3 groups by treatment:35 eyes served as the control group,39 eyes received a 5-mg intralesional injection of 5-FU weekly for 2 weeks,and 35 eyes received one 20-mg intralesional injection of triamcinolone.All groups received 1% prednisolone acetate eye drops 4 times daily for 8 weeks.Main Outcome Measures:Recurrence rate,success rate,and survival analysis were compared among the groups.Results:With a mean follow-up time of 10.9± 5.5 months(range,6-26 months) ,the success rates of the 5-fluorouracil and triamcinolone groups were higher than the control group(87.2%,71.4%,and 48.6%,respectively) .5-fluorouracil was significantly(P=0.001) more effective in inhibiting the recurrence of pterygium compared with the control group at all time points during follow-up.Kaplan-Meier survival analysis showed that the recurrence-free period of pterygium in the 5-FU group was significantly(P=0.005) longer than that of the control group but not in the triamcinolone group compared with the controls(P=0.063) .There was no significant difference between the 5-FU group and the triamcinolone group(P=0.362) .Minimal reversible complications such as steroid-induced glaucoma and superficial punctate epitheliopathy developed during the study.Conclusions:Intralesional injection of 5-FU and triamcinolone was more effective in inhibiting the recurrence of pterygium than topical steroid alone,with the results in the 5-FU group reaching statistical significance. Objective: To study the efficacy of subconjunctival 5-fluorouracil (5-FU) and triamcinolone injection in halting the progression of impending recurrent pterygium. Design: Randomized, prospective, controlled trial clinical trial. Participants: One hundred nine patients who had undergone pterygium excision within The previous 6 months and developed grade 3 characteristics (impending recurrent pterygium). Methods: A total of 109 eyes with impending recurrent pterygium were stratified randomly into 3 groups by treatment: 35 eyes served as the control group, 39 eyes received a 5-mg intralesional injection of 5-FU weekly for 2 weeks, and 35 eyes received one 20-mg intralesional injection of triamcinolone. All groups received 1% prednisolone acetate eye drops 4 times daily for 8 weeks. Main Outcome Measures: Recurrence rate, success rate, and survival analysis were compared among the groups. Results: With a mean follow-up time of 10.9 ± 5.5 months (range, 6-26 months), the success rates of the 5-fluorouracil and triamci 5-fluorouracil was significantly (P = 0.001) more effective in inhibiting the recurrence of pterygium compared with the control group at all time points during (p = 0.001) nolone groups were higher than the control group (87.2%, 71.4%, and 48.6%, respectively) follow-up. Kaplan-Meier survival analysis showed that the recurrence-free period of pterygium in the 5-FU group was significantly (P = 0.005) longer than that of the control group but not in the triamcinolone group compared with the controls (P = 0.063). There was no significant difference between the 5-FU group and the triamcinolone group (P = 0.362) .Minimal reversible complications such as steroid-induced glaucoma and superficial punctate epitheliopathy developed during the study. Conclusions: Intralesional injection of 5- FU and triamcinolone was more effective in inhibiting the recurrence of pterygium than topical steroid alone, with the results in the 5-FU group reaching statistical significance.