Purpose: Iris neovascularization (INV) and anterior chamber angle neovascularization after radiotherapy for uveal melanoma may lead to neovascular glaucoma and enucleation. However, neovascularization of the anterior ocular segment may respond favorably to treatment with panretinal photocoagulation. The purpose of this study was to evaluate the frequency, interval to development, and predisposing factors of anterior ocular segment neovascularization following iodine 125 (I125)- brachytherapy for uveal melanoma. Design: Retrospective, interventional, consecutive case series. Participants: Sixty- five patients (65 eyes), consecutively treated with I125 brachytherapy for uveal melanoma from 1995 through 2000 and followed up after radiation therapy for 24 months or more. Methods: Clinical findings and ultrasonography characteristics as well as treatment parameters were analyzed. Main Outcome Measures: The frequency of INV was determined and the interval to development of INV as well as the predisposing factors were analyzed statistically. Results: In 15 of 65 eyes (23% ), INV was detected after I125 brachytherapy at a mean± standard deviation of 26.66± 11.63 months (median, 24 months; range, 9- 48 months). Risk factors displaying the stronger correlation with INV were greater maximal tumor height (P< 0.01), greater tumor vascularity (P< 0.01), and disinsertion of horizontal rectus muscles (P=0.01). Conclusions: After I125 brachytherapy for choroidal melanoma, INV developed in 23% of eyes and was correlated with larger tumor size, greater tumor vascularity, and disinsertion of a horizontal rectus muscle. However, neovascularization of the anterior ocular segment may respond favorably to treatment with panretinal photocoagulation. The purpose of this study was to evaluate the frequency, interval to development, and predisposing factors of anterior ocular segment neovascularization following iodine 125 (I125) -brachytherapy for uveal melanoma. Design: Retrospective, interventional, consecutive case series. Participants: Sixty- five patients (65 eyes), consecutively treated with I125 brachytherapy for uveal melanoma from 1995 through 2000 and followed up radiation therapy for 24 months or more. Methods: Clinical findings and ultrasonography characteristics as well as treatment parameters were analyzed. Main Outcome Measures: The frequency of INV was determined and the interval to development of INV as well as the Results: In 15 of 65 eyes (23%), INV was detected after I125 brachytherapy at a mean ± standard deviation of 26.66 ± 11.63 months (median, 24 months; range, 9- 48 months). Risk Factors displaying the stronger correlation with INV were greater maximal tumor height (P <0.01), greater tumor vascularity (P <0.01), and disinsertion of horizontal rectus muscles (P = 0.01). Conclusions: After I125 brachytherapy for choroidal melanoma, INV developed in 23% of eyes and was correlated with larger tumor size, greater tumor vascularity, and disinsertion of a horizontal rectus muscle.