Aims To report visual acuity (VA) outcomes following chemotherapy for optic pathway glioma (OPG) in children with or without neurofibromatosis type-1 (NF1) and to analyse associated risk factors.

Methods A prospective, multicentre, cohort study involving 155 children treated between September 2004 and December 2012. Initial and final VA was used for per-eye and per-subject analysis. Correlation tests were performed to determine whether initial VA predicted final VA. Logistic regression was used to determine whether age and tumour location were associated risk factors.

Results 90 children had complete ophthalmological data. At initiation of chemotherapy, 26% and 49% of eyes with NF1-OPG and sporadic OPG, respectively, had VA of ≥0.7 log of the minimum angle of resolution (logMAR). At final visit, per eye, 49% had ≤0.2, 23% had 0.30–0.60 and 28% had VA≥0.70 logMAR in the NF1-OPG group. In the sporadic OPG group, per eye, 32% had ≤0.2, 11% had VA 0.30–0.60 and 57% had ≥0.70 logMAR. Children with sporadic OPG, per eye, were significantly less likely to have VA outcomes ≤0.60 logMAR compared with children with NF1-OPG (OR=0.30; 95% CI 0.16 to 0.56; P<0.0001). Per subject, VA improved in 24%, remained stable in 35% and worsened in 41% of children with NF1-OPG and improved in 18%, remained stable in 43% and worsened in 39% of children with sporadic OPG.

Conclusions Children with and without NF1 demonstrated the same rate of VA improvement, stabilisation or worsening; however, children with sporadic OPG had a poorer VA outcome. Better initial VA, older age, absence of postchiasm tumour and presence of NF1 were associated with improved or stable VA outcomes.