title: Orbital subperiosteal hemorrhage while scuba diving.
abstract: OBJECTIVE
  To report an uncommon case of unilateral subperiosteal hemorrhage while scuba diving involving the orbit, a condition characterized by proptosis and associated severe ocular motility disturbances with displacement of the eyeball.
  
  
  METHODS
  Observational case report.
  
  
  RESULTS
  Unilateral subperiosteal hemorrhage in a 31-year-old woman while scuba diving at a depth of 20 meters. This was documented by clinical and radiographic examination. Computed tomography (CT) scan demonstrated a subperiosteal hemorrhage as a self-limited mass protruding into the left orbit. The process resolved without treatment and without visual or motility sequelae. A CT-scan, nuclear magnetic resonance, and conventional angiography did not show any venous abnormalities in the brain.
  
  
  CONCLUSIONS
  During scuba diving at a depth of 20 meters, the pressure is three atmospheres, whereas within the diving mask the pressure is one atmosphere if it is not equilibrated; thus, a negative pressure is created within the mask. Small vessels can be broken in the conjunctiva or subperiosteal space by this force. It is important to exclude vascular abnormalities, especially if there is a positive family history.
authors.affiliation: Department of Ophthalmology, Complutense University, Madrid, Spain.
authors.forename: Isabel
authors.initials: I
authors.lastname: Gómez-Ledesma
authors.forename: Enrique
authors.initials: E
authors.lastname: Mencía-Gutíerrez
authors.forename: Esperanza
authors.initials: E
authors.lastname: Gutiérrez-Díaz
authors.forename: María A
authors.initials: MA
authors.lastname: Alonso-Santiago
mesh_terms: D000328:Adult; D004242:Diving / Q000009:adverse effects*; D005130:Eye Hemorrhage / Q000175:diagnosis* / Q000209:etiology; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D035583:Rare Diseases; D012075:Remission, Spontaneous; D019315:Retrobulbar Hemorrhage / Q000175:diagnosis* / Q000209:etiology; D018570:Risk Assessment; D014057:Tomography, X-Ray Computed