title: Visual loss in children with neurofibromatosis type 1 and optic pathway gliomas: relation to tumor location by magnetic resonance imaging.
abstract: OBJECTIVE
  To examine the potential for visual acuity loss, and its relation to extent and location of optic pathway gliomas in a cohort of children with neurofibromatosis type 1 studied with magnetic resonance imaging.
  
  
  METHODS
  We reviewed the neuro-ophthalmologic records and brain/orbital magnetic resonance imaging scans for 43 consecutive pediatric patients with neurofibromatosis type 1 and optic pathway gliomas who were followed at the Children's Hospital of Philadelphia. The presence of visual loss, defined as abnormal visual acuity for age in one or both eyes, was determined. Optic pathway gliomas were classified by tumor extent and location according to involvement of the optic nerves, chiasm, and postchiasmal structures by magnetic resonance imaging.
  
  
  RESULTS
  Involvement of the optic tracts and other postchiasmal structures at tumor diagnosis was associated with a significantly higher probability of visual acuity loss (P =.048, chi-square test). Visual loss was noted in 20 of 43 patients (47%) at a median age of 4 years; however, three patients developed visual acuity loss for the first time during adolescence.
  
  
  CONCLUSIONS
  In pediatric patients with neurofibromatosis type 1 and optic pathway gliomas, the likelihood of visual loss is dependent on the extent and location of the tumor by magnetic resonance imaging and is particularly associated with involvement of postchiasmal structures. Furthermore, older age during childhood (adolescence) does not preclude the occurrence of visual loss. Close follow-up beyond the early childhood years, particularly for those with postchiasmal tumor, is recommended.
authors: Division of Neuro-Ophthalmology, Department of Neurology, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA. lbalcer@mail.med.upenn.edu
authors: L J
authors: LJ
authors: Balcer
authors: G T
authors: GT
authors: Liu
authors: G
authors: G
authors: Heller
authors: L
authors: L
authors: Bilaniuk
authors: N J
authors: NJ
authors: Volpe
authors: S L
authors: SL
authors: Galetta
authors: P T
authors: PT
authors: Molloy
authors: P C
authors: PC
authors: Phillips
authors: A J
authors: AJ
authors: Janss
authors: S
authors: S
authors: Vaughn
authors: M G
authors: MG
authors: Maguire
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D006801:Humans; D008279:Magnetic Resonance Imaging; D009456:Neurofibromatosis 1 / Q000175:diagnosis*; D009897:Optic Chiasm / Q000473:pathology*; D020339:Optic Nerve Glioma / Q000175:diagnosis*; D019574:Optic Nerve Neoplasms / Q000175:diagnosis*; D014786:Vision Disorders / Q000175:diagnosis*; D014792:Visual Acuity