Background/aims: To evaluate the efficacy of intracameral recombinant tissue plasminogen activator (r-TPA) in prevention of fibrinous effusion after lensectomy, anterior vitrectomy, and posterior chamber intraocular lens (PCIOL) implantation in patientswith congenital cataract. Methods: The studywas done as a double masked randomised clinical trial between April 2002 and November 2003 in Farabi Eye Hospital. 34 eyes of 26 patients with congenital cataract were included in the study and randomised into two groups (18 cases and 16 controls). Mean agewas 8.1 years (3-14 years). Each eye underwent lensectomy and anterior vitrectomy with PCIOL implantation. At the end of surgery 20 μg r-TPA was injected intracamerally in the case group. The control group received only balanced salt solution. All patients received periocular, systemic, and topical steroids after surgery. Patients underwent follow up examinations for 3 months. Results: The incidence of intraocular fibrin membrane formation was significantly lower in the case group on days 1, 3, 7, 14 (p=0.02, p=0.01, p=0.01, and p=0.01, respectively, χ2 test), but there was no significant difference on days 30 and 90. The frequency of pigmented intraocular lens precipitates was significantly lower in the case group at the end of the third month (p < 0.001, χ2 test). No gross ocular side effects were noted after r-TPA injection. Conclusion: It seems that prophylactic intracameral r-TPA is effective in prevention of fibrinous effusion at least in the first 2 weeks after cataract extraction in the paediatric age group and decreases the incidence of pigmented IOL precipitates. Background / aims: To evaluate the efficacy of intracameral recombinant tissue plasminogen activator (r-TPA) in prevention of fibrinous effusion after lensectomy, anterior vitrectomy, and posterior chamber intraocular lens (PCIOL) implantation in patients with congenital cataract. Methods: The studywas done as a double masked randomized clinical trial between April 2002 and November 2003 in Farabi Eye Hospital. 34 eyes of 26 patients with congenital cataract were included in the study and randomized into two groups (18 cases and 16 controls). Mean agewas 8.1 years (3- At the end of surgery 20 μg r-TPA was injected intracamerally in the case group. The control group received only balanced salt solution. All patients received periocular, systemic, and topical steroids after surgery. Patients underwent follow up exams for 3 months. Results: The incidence of intraocular fibrin membrane formation w as significantly lower in the case group on days 1, 3, 7, 14 (p = 0.02, p = 0.01, p = 0.01, and p = 0.01, respectively, χ2 test), but there was no significant difference on days 30 and 90. The frequency of pigmented intraocular lens precipitates was significantly lower in the case group at the end of the third month (p <0.001, χ2 test). No gross ocular side effects were noted after r-TPA injection. Conclusion: It seems that prophylactic intracameral r-TPA is effective in prevention of fibrinous effusion at least in the first 2 weeks after cataract extraction in the pediatric age group and decreases the incidence of pigmented IOL precipitates.