Visual morbidity, long-term outcome and prognostic factors in infants and young children with optic pathway low-grade glioma

Background. Optic pathway gliomas (OPG) in infants and young children (IYC) are associated with significant long-term morbidity, but visual outcomes in this high-risk group remain poorly characterized. Methods: We retrospectively reviewed clinical, ophthalmologic, and radiological data from 81 children diagnosed with OPG before age 3 and followed at a single institution between 1981 and 2020. Best-corrected visual acuity (BCVA) was assessed using age-adjusted criteria and REiNS recommendations. Survival outcomes and prognostic factors were analysed using Kaplan-Meier and regression models. Results: Thirty-one children underwent initial surgery, four of whom had no further treatment. Sixty-six were treated with chemotherapy (62) or radiotherapy (4) at diagnosis, while 11 were initially observed. At presentation, 74% had abnormal-for-age BCVA, and 33% met criteria for bilateral visual impairment. After a median 11-year follow-up, 81.5% showed abnormal vision, 45.7% were visually impaired, and 26% were bilaterally blind. Only 36% showed BCVA improvement, while 32% worsened. The 10-year visual progression-free survival was 41.3%. Post-chiasmatic tumor involvement was the only independent predictor of visual progression (HR 2.91, P = .033). Most cases of visual deterioration occurred within the first 2 years, but late events up to 16 years post-diagnosis were also observed. Conclusions: IYC with OPG suffer from substantial and often irreversible visual morbidity, frequently already present at diagnosis. Despite long-term survival, functional visual outcomes remain poor. Our findings underscore the urgent need for earlier, vision-directed interventions and long-term visual monitoring. This large single-center cohort provides a robust benchmark for future prospective studies.