title: The refractive changes and long-term (3 years) results of radial keratotomy performed at high altitude.
abstract: OBJECTIVE
  To evaluate the development of regression or progression following radial keratotomy (RK) performed at high altitude (1,720 meters) at long-term follow-up (3 years).
  
  
  METHODS
  Thirty-nine eyes of 21 myopia patients (between -3.25 D and -11.00 D) whose ages were 19-32 years were included in the study. The RK procedures were performed in standard Russian style.
  
  
  RESULTS
  The average spherical equivalent cycloplegic refractions were -5.49 D +/- 2.08 (SD) preoperatively, -1.64 +/- 1.59 D in the short-term (3.41 +/- 1.46 months) and -1.40 +/- 1.71 D in the long-term (30.72 +/- 4.36 months) follow-up period. There was no statistically significant difference between these values at the short- and long-term follow-up measurements (t = -1.57, P =.12).
  
  
  CONCLUSIONS
  The refractive changes following RK performed at high altitude occur through a combination of both the direct effect of reduced barometric pressure and the edematous corneal expansion because of hypoxia. An ophthalmologist performing RK surgery at high altitude must consider the long-lasting therapeutic effects of high altitude surgery compared to surgery at sea level.
authors: Department of Ophthalmology, Faculty of Medicine, The University of Yüzüncü Yil, Van, Turkey.
authors: T
authors: T
authors: Yaşar
authors: S
authors: S
authors: Simşek
authors: O F
authors: OF
authors: Yilmaz
mesh_terms: D000328:Adult; D000531:Altitude; D003315:Cornea / Q000503:physiopathology* / Q000601:surgery; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007646:Keratotomy, Radial; D008297:Male; D009216:Myopia / Q000503:physiopathology* / Q000601:surgery; D012029:Refraction, Ocular / Q000502:physiology*; D016896:Treatment Outcome