ID #476 Increased Prevalence of Optic Nerve Hypoplasia in Neurofibromatosis Type 1

Introduction Neurofibromatosis type 1 (NF1) is associated with distinct ophthalmologic findings, including optic pathway gliomas (OPGs). Optic nerve hypoplasia (ONH) has not previously been associated with NF1. This study describes prevalence and risk factors for ONH in children with NF1. Methods Pediatric patients with NF1 evaluated by both oncology and ophthalmology at Cincinnati Children’s Hospital were reviewed. Relative optic nerve size was assessed by ultra-wide-field imaging using the ratio of horizontal-disc diameter to fovea-disc distance on fundus photographs, supplemented by spectral-domain OCT. Demographic, clinical, and imaging variables were analyzed for associations with ONH. Results Among 175 charts reviewed, 90 patients (174 eyes) had fundus photographs suitable for analysis (Table). ONH was identified in 17% of the eyes and 21% of patients with NF1, compared to < 0.05% in the general population (p < 0.001). NF1 mutation locus was not associated with ONH. ONH was observed in patients with and without OPGs and not associated with OPG in the affected eye (p = 0.35). ONH was not associated with sex, NF1 inheritance, exposure to chemotherapy or MEK inhibitor, age, visual acuity, or retinal nerve fiber layer thickness. Conclusion/Relevance ONH is more common in children with NF1 but is not associated with increased risk of OPG or visual acuity decline. ONH alone should not be considered an indication for OPG treatment. Further research is warranted to clarify its etiology and relevance in NF1.