title: Delayed diagnosis in a sight-threatening lesion.
abstract: BACKGROUND
  Acute chiasmal compression has several aetiologies including pituitary apoplexy, a medical emergency caused by acute haemorrhagic or ischemic infarction in pituitary macroadenomas. Clinical diagnosis can often be difficult as the patient is frequently unaware of an existing adenoma. Delayed diagnosis may lead to increased morbidity and mortality.
  
  
  OBJECTIVE
  We describe a rarely presenting case report of acute chiasmal compression with unusual visual symptoms of hemifield slide, with initial delayed diagnosis.
  
  
  CONCLUSIONS
  Knowledge of this infrequently presenting visual phenomenon may aid in rapid diagnosis, appropriate imaging and intervention leading to improved visual and systemic outcomes.
authors.affiliation: Department of Ophthalmology, Beaumont Hospital, Dublin 9, Ireland.
authors.forename: E
authors.initials: E
authors.lastname: O'Neill
authors.forename: P
authors.initials: P
authors.lastname: Connell
authors.forename: D
authors.initials: D
authors.lastname: Rawluk
authors.forename: P
authors.initials: P
authors.lastname: Logan
mesh_terms: D006801:Humans; D008297:Male; D008875:Middle Aged; D009897:Optic Chiasm / Q000601:surgery*; D009901:Optic Nerve Diseases / Q000175:diagnosis* / Q000209:etiology / Q000601:surgery; D010899:Pituitary Apoplexy / Q000150:complications / Q000175:diagnosis* / Q000601:surgery; D013997:Time Factors