title: Optic disc edema, globe flattening, choroidal folds, and hyperopic shifts observed in astronauts after long-duration space flight.
abstract: OBJECTIVE
  To describe the history, clinical findings, and possible etiologies of ophthalmic findings discovered in 7 astronauts after long-duration space flight, and document vision changes in approximately 300 additional astronauts.
  
  
  METHODS
  Retrospective, observational examination of ophthalmic findings in 7 astronauts and analysis of postflight questionnaires regarding in-flight vision changes in approximately 300 additional astronauts.
  
  
  METHODS
  Seven astronauts with ophthalmic anomalies upon return from long-duration space missions to the International Space Station and 300 additional astronauts who completed postflight questionnaires regarding in-flight vision changes.
  
  
  METHODS
  Before and after long-duration space flight, all 7 subjects underwent complete eye examinations, including cycloplegic and/or manifest refraction and fundus photography. Six underwent postmission optical coherence tomography (OCT) and magnetic resonance imaging (MRI); 4 had lumbar punctures (LP). Approximately 300 astronauts were queried regarding visual changes during space missions.
  
  
  METHODS
  Refractive change, fundus photograph examination, retina OCT, orbital MRI, LP opening pressures, and examination of visual acuity data.
  
  
  RESULTS
  After 6 months of space flight, 7 astronauts had ophthalmic findings, consisting of disc edema in 5, globe flattening in 5, choroidal folds in 5, cotton wool spots (CWS) in 3, nerve fiber layer thickening by OCT in 6, and decreased near vision in 6 astronauts. Five of 7 with near vision complaints had a hyperopic shift ≥+0.50 diopters (D) between pre/postmission spherical equivalent refraction in 1 or both eyes (range, +0.50 to +1.75 D). These 5 showed globe flattening on MRI. Lumbar punctures performed in the 4 with disc edema documented opening pressures of 22, 21, 28, and 28.5 cm H(2)O performed 60, 19, 12, and 57 days postmission, respectively. The 300 postflight questionnaires documented that approximately 29% and 60% of astronauts on short and long-duration missions, respectively, experienced a degradation in distant and near visual acuity. Some of these vision changes remain unresolved years after flight.
  
  
  CONCLUSIONS
  We hypothesize that the optic nerve and ocular changes we describe may result from cephalad fluid shifts brought about by prolonged microgravity exposure. The findings we report may represent parts of a spectrum of ocular and cerebral responses to extended microgravity exposure.
  
  
  BACKGROUND
  The authors have no proprietary or commercial interest in any of the materials discussed in this article.
authors.affiliation: Department of Ophthalmology, Alaska Native Medical Center, Anchorage, AK 99508, USA. tmader@acsalaska.net
authors.forename: Thomas H
authors.initials: TH
authors.lastname: Mader
authors.forename: C Robert
authors.initials: CR
authors.lastname: Gibson
authors.forename: Anastas F
authors.initials: AF
authors.lastname: Pass
authors.forename: Larry A
authors.initials: LA
authors.lastname: Kramer
authors.forename: Andrew G
authors.initials: AG
authors.lastname: Lee
authors.forename: Jennifer
authors.initials: J
authors.lastname: Fogarty
authors.forename: William J
authors.initials: WJ
authors.lastname: Tarver
authors.forename: Joseph P
authors.initials: JP
authors.lastname: Dervay
authors.forename: Douglas R
authors.initials: DR
authors.lastname: Hamilton
authors.forename: Ashot
authors.initials: A
authors.lastname: Sargsyan
authors.forename: John L
authors.initials: JL
authors.lastname: Phillips
authors.forename: Duc
authors.initials: D
authors.lastname: Tran
authors.forename: William
authors.initials: W
authors.lastname: Lipsky
authors.forename: Jung
authors.initials: J
authors.lastname: Choi
authors.forename: Claudia
authors.initials: C
authors.lastname: Stern
authors.forename: Raffi
authors.initials: R
authors.lastname: Kuyumjian
authors.forename: James D
authors.initials: JD
authors.lastname: Polk
mesh_terms: D000337:Aerospace Medicine; D018480:Astronauts; D015862:Choroid Diseases / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology; D005128:Eye Diseases / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology; D006801:Humans; D006956:Hyperopia / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology; D007427:Intracranial Pressure / Q000502:physiology; D007429:Intraocular Pressure / Q000502:physiology; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010211:Papilledema / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology; D012189:Retrospective Studies; D013026:Space Flight; D013129:Spinal Puncture; D011795:Surveys and Questionnaires; D041623:Tomography, Optical Coherence; D014786:Vision Disorders / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology; D014792:Visual Acuity / Q000502:physiology; D014893:Weightlessness / Q000009:adverse effects*