title: Changes in central corneal thickness, intraocular pressure, and oxidation/antioxidation parameters at high altitude.
abstract: BACKGROUND
  The authors aimed at investigating ophthalmological changes at high altitude and correlating this with blood oxidation/antioxidation parameters.
  
  
  METHODS
  There were 40 volunteers who participated in the study. Initial ophthalmological examinations were performed at 3543 ft (1080 m) and repeated on the following day after the participants climbed to an altitude of 9186 ft (2800 m) on Mt. Erciyes, Turkey. Venous blood samples were taken at both altitudes to evaluate total oxidative system (TOS) and antioxidative system (TAS) levels.
  
  
  RESULTS
  IOP-right eyes at 3543 ft (1080 m) was 13.23 +/- 0.43 mmHg and significantly increased to 14.45 +/- 0.56 mmHg at 9186 ft (2800 m). LOP-left eyes at 3543 ft (1080 m) was 13.50 +/- 0.44 mmHg and increased to 14.13 +/- 0.54 mmHg at 9186 ft (2800 m) (P = n.s.). Central corneal thickness (CCT) of the right eyes was 540.98 +/- 4.34 microm at 3543 ft (1080 m) and significantly increased to 549.73 +/- 4.59 microm at 9186 ft (2800 m). CCT of the left eyes was 542.13 +/- 29.01 microm at 3543 ft (1080 m) and significantly increased to 547.23 +/- 4.59 microm at 9186 ft (2800 m). Spherical equivalent refraction of right or left eyes did not show any significant changes. TOS at 3543 ft (1080 m) was 5.33 +/- 0.76 micromol H2O2 equiv/L and significantly increased to 7.55 +/- 0.82 micromol H2O2 equiv/L at 9186 ft (2800 m). TAS at 3543 ft (1080 m) was 2.45 +/- 0.12 micromol H2O2 equiv/L and decreased to 2.22 +/- 0.08 micromol H2O2 equiv/L (P = n.s.) at 9186 ft (2800 m). There was a positive correlation between TAS and LOP at 9186 ft (2800 m).
  
  
  CONCLUSIONS
  Increased CCT can be related to stromal edema caused by hypoxia's effect on corneal endothelial function. Although TOS increased at high altitude, TAS did not show any parallel increase. Since this was nonacclimatized climbing, the antioxidant system could not have reached sufficient levels to counterbalance the observed oxidant stress.
authors.affiliation: Erciyes University Medical Faculty, Department of Ophthalmology, Kayseri 38039, Turkey. sarperkarakucuk@gmail.com
authors.forename: Sarper
authors.initials: S
authors.lastname: Karakucuk
authors.forename: Metin
authors.initials: M
authors.lastname: Mujdeci
authors.forename: Gulden
authors.initials: G
authors.lastname: Baskol
authors.forename: Hatice
authors.initials: H
authors.lastname: Arda
authors.forename: Koray
authors.initials: K
authors.lastname: Gumus
authors.forename: Ayse
authors.initials: A
authors.lastname: Oner
mesh_terms: D000293:Adolescent; D000328:Adult; D000531:Altitude; D000975:Antioxidants / Q000032:analysis*; D001794:Blood Pressure / Q000502:physiology; D003315:Cornea / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D010092:Oximetry; D010100:Oxygen / Q000097:blood*; D014463:Ultrasonography; D055815:Young Adult
chemical_list: D000975:Antioxidants; D010100:Oxygen