title: Intraocular pressure measured at ground level and 10,000 feet.
abstract: BACKGROUND
  Intraocular pressure (IOP) may be subject to change during altitude exposure. This may be an important consideration for long-haul flights. In this study, intraocular pressure change was investigated following exposure to an altitude of 10,000 ft during flight in an unpressurized aircraft.
  
  
  METHODS
  We measured the IOP of the right eye of 20 healthy volunteers (18 men, 2 women; mean age 34.6 +/- 9.5 yr) at a ground level of 1,760 ft (536 m) above the sea level (ASL) using a Tono-Pen XL tonometer. We then repeated the measurements during a flight in the unpressurized cabin of a CASA (CN235-100 M) aircraft after gaining an altitude of 10,000 ft (3,048 m) ASL. Changes in the IOP were evaluated.
  
  
  RESULTS
  Mean IOP was 16.2 +/- 2.46 mmHg at ground level and 15.0 +/- 2.61 mmHg at 10,000 ft (3,048 m) ASL. IOP was reduced in 13 eyes, increased in 6 eyes, and remained unchanged in 1 eye. The mean change in IOP was 1.2 +/- 2.69 mmHg. However, this was not statistically significant (p = 0.06).
  
  
  CONCLUSIONS
  Acute change in altitude resulted in a statistically non-significant reduction in IOP in healthy subjects.
authors.affiliation: GATA School of Medicine, Etlik, Ankara, Turkey 06010. atillabayer@hotmail.com
authors.forename: Atilla
authors.initials: A
authors.lastname: Bayer
authors.forename: Erhan
authors.initials: E
authors.lastname: Yumuşak
authors.forename: Omer F
authors.initials: OF
authors.lastname: Sahin
authors.forename: Yusuf
authors.initials: Y
authors.lastname: Uysal
mesh_terms: D000328:Adult; D000531:Altitude; D005260:Female; D006801:Humans; D007429:Intraocular Pressure; D008297:Male; D008875:Middle Aged; D013696:Temperature