This study aimed to observe the long-term effect of enucleation combined with primary orbital implantation in children with histopathologic optic nerve invasive retinoblastoma (RB).We retrospectively analyzed the clinical data and outcomes of children with RB optic nerve invasion confirmed by histopathology who underwent enucleation combined with primary orbital implantation between March 2010 and April 2014 in Beijing Tongren Hospital. The follow-up time ranged from 81 to 129 months, with a mean follow-up of 96 ± 14 months.A total of 59 children were included in this study. There were 32 males and 27 females; 52 children were affected in one eye and seven children in both eyes. The time from onset of symptoms to visit was between 3 days and 16 months, with a mean of 2.2 ± 2.8 months. The age at the of surgery was between 2 and 65 months, with an average of 24 ± 13 months. Patients were classified based on the degree of optic nerve invasion into four grades: grade 1 (invasion of prelaminar) in 28 cases, grade 2 (invasion of laminar) in 14 cases, grade 3 (invasion of retrolaminar but not reaching the optic nerve transection) in 16 cases, and grade 4 (invasion of the optic nerve transection) in 1 case. Post-operatively, all children were treated with 0-9 cycles of intravenous chemotherapy based on histopathology results from the removed eye. Of the 59 children, 13 had postoperative complications, and one died from recurrence. The survival rate was 98% (58/59). There was one case of orbital implant exposure, one of orbital cellulitis, six of enophthalmos and superior sulcus deformity, two of blepharoptosis, one of granuloma complicated with blepharoptosis, and one with a subconjunctival cyst.For children with RB histopathologic invasion of the optic nerve, enucleation combined with primary orbital implantation reveals future potential treatment options when combined with a full course of intravenous chemotherapy.Copyright © 2022 Wang, Liu, Li, Wang, Xu, Guo, Zhang and Ma.