title: [High altitude retinopathy: report of 3 cases].
abstract: OBJECTIVE
  To report three cases of vision loss occurring at high altitude.
  
  
  METHODS
  Three patients aged 27 to 52 years presented with scotoma and/or visual acuity deficit upon their return from high altitude expeditions above 6000 m. Fundus examination revealed multiple posterior pole hemorrhages, resolving completely by two months.
  
  
  CONCLUSIONS
  Exposure to hypobaric hypoxia at high altitude leads to adaptation mechanisms in order to maintain retinal oxygenation. Certain individuals have an inadequate autoregulatory response and develop signs of "high altitude retinopathy" (HAR), including retinal hemorrhages most often, with occasional vitreous hemorrhage, optic nerve head edema and retinal vein occlusion. The pathophysiology of HAR is not well understood. Identified risk factors include altitude above 4000 m, rapid ascent and personal susceptibility. Age and fitness are unrelated. Association with acute mountain sickness, high-altitude pulmonary edema and high-altitude cerebral edema is still controversial.
  
  
  CONCLUSIONS
  Retinal hemorrhages occurring after high-altitude hiking are an early manifestation of HAR and are part of high-altitude illness. HAR usually occurs at altitudes above 4000 m, is generally asymptomatic, and spontaneously regresses. A maladaptive autoregulatory response to hypobaric hypoxia appears to be the cause of HAR.
authors.affiliation: Service d'ophtalmologie, hôpital d'instruction des armées Desgenettes, 108, boulevard Pinel, 69003 Lyon, France. Electronic address: aurelierusso.m@gmail.com.
authors.forename: A
authors.initials: A
authors.lastname: Russo
authors.affiliation: Service d'ophtalmologie, hôpital d'instruction des armées Desgenettes, 108, boulevard Pinel, 69003 Lyon, France.
authors.forename: E
authors.initials: E
authors.lastname: Agard
authors.affiliation: Cabinet privé, 509, route des Pèlerins, 74400 Chamonix-Mont-Blanc, France.
authors.forename: J-P
authors.initials: JP
authors.lastname: Blein
authors.affiliation: Service d'ophtalmologie, hôpital d'instruction des armées Desgenettes, 108, boulevard Pinel, 69003 Lyon, France.
authors.forename: H El
authors.initials: HE
authors.lastname: Chehab
authors.affiliation: Service d'ophtalmologie, hôpital d'instruction des armées Desgenettes, 108, boulevard Pinel, 69003 Lyon, France.
authors.forename: C
authors.initials: C
authors.lastname: Lagenaite
authors.affiliation: Service d'ophtalmologie, hôpital d'instruction des armées Desgenettes, 108, boulevard Pinel, 69003 Lyon, France.
authors.forename: G
authors.initials: G
authors.lastname: Ract-Madoux
authors.affiliation: Service d'ophtalmologie, hôpital d'instruction des armées Desgenettes, 108, boulevard Pinel, 69003 Lyon, France.
authors.forename: C
authors.initials: C
authors.lastname: Dot
mesh_terms: D000328:Adult; D000399:Air Pressure; D000532:Altitude Sickness / Q000150:complications*; D006801:Humans; D000860:Hypoxia / Q000150:complications; D008297:Male; D008875:Middle Aged; D008889:Military Personnel; D009051:Mountaineering; D010100:Oxygen / Q000097:blood; D012075:Remission, Spontaneous; D012160:Retina / Q000378:metabolism; D012166:Retinal Hemorrhage / Q000209:etiology* / Q000503:physiopathology; D012307:Risk Factors; D012607:Scotoma / Q000209:etiology* / Q000503:physiopathology; D041623:Tomography, Optical Coherence; D014792:Visual Acuity; D058609:Visual Field Tests
chemical_list: D010100:Oxygen
keywords: Haute altitude; High altitude; Hypobaric hypoxia; Hypoxie hypobare; Hémorragie rétinienne; Retinal hemorrhages; Rétinopathie