Screening for neurofibromatosis type 1-related optic pathway gliomas: a systematic review

Neurofibromatosis-type 1 (NF1) is a genetic disorder characterized by developing optic pathway gliomas (OPGs) in 15%-20% of patients with higher estimates where consanguinity is prevalent. Clinically, NF1-OPG might be unpredictable with the risk of OPG progression and visual impairment. The optimal time for screening is controversial. We aim to identify the mean/median age at diagnosis of NF1-OPG and its clinical spectrum.

A systematic review of PubMed, Web of Science, and Embase databases was conducted for English-language publications from January 1993 to October 2025, exploring the visual screening of OPGs in NF1 patients, following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and registered in the Prospective Register of Systematic Reviews (PROSPERO ID: CRD420251036244). Inclusion criteria focused on studies reporting the age at OPG diagnosis and visual manifestations in NF1 patients. Data were extracted on demographics, age at NF1 and OPG diagnosis, tumour location (using the Dodge classification), and presenting symptoms. Sixteen studies met the inclusion criteria.

Among 4 739 NF1 patients, 818 had OPGs, with prevalence ranging from 4.2% to 46.7%. The age at NF1 diagnosis ranged from 0 to 132 months (mean: 18-38 months), and at OPG diagnosis from 0-240 months (median: 29-58 months). Approximately 58.4% of OPGs were asymptomatic, and 25% were above the age of 5 years. Among symptomatic patients, the most frequent presentations included decreased visual acuity (62%), abnormal optic disc (45%), proptosis (20%), strabismus (12%), and visual field defects (7%).

NF1-related OPGs typically present early within 6 years of age. Early ophthalmologic and/or radiologic screening at the time of NF1 diagnosis enhances the detection of silent OPGs.