title: Travel to high mountain elevations following vitrectomy with intraocular gas.
abstract: OBJECTIVE
  To evaluate the effects and safety of travel by land through high mountainous elevations after surgery in patients who have undergone pars plana vitrectomy with intraocular gas.
  
  
  METHODS
  A retrospective cohort study of 75 patients post pars plana vitrectomy with intraocular gas who traveled by land through mountain elevations of up to 3895 feet above sea level within 1 day of surgery.
  
  
  RESULTS
  The average rate of ascent through the mountains was 29 ft/min and the maximum theoretical ocular compensation was 0.57 cubic centimeters (cc), which occurred at 4259 feet above sea level. A statistically significant change in postoperative intraocular pressure was found when compared with preoperative (P = 0.010), with two factors influencing this change: the type of gas (C3F8, P = 0.038) and lens status (pseudophakic, P = 0.010), with a mean final intraocular pressure still within the safe range. There were no cases of retinal vascular occlusion, acute elevations of intraocular pressure requiring surgical intervention, or symptomatic visual field loss attributable to elevated intraocular pressure.
  
  
  CONCLUSIONS
  It seems that patients with a complete fill of intraocular gas after pars plana vitrectomy may travel safely by land through mountains with a peak ascent of 3895 feet, final ascent of 2787 feet, and a mean rate of 29 ft/min. These findings can significantly impact patient costs and convenience.
authors.affiliation: Department of Ophthalmology and Visual Sciences, University of British Columbia, Vancouver, BC, Canada. levasseur.steve@gmail.com
authors.forename: Steve D
authors.initials: SD
authors.lastname: Levasseur
authors.forename: Firas M
authors.initials: FM
authors.lastname: Rahhal
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000531:Altitude; D058450:Endotamponade; D005260:Female; D005466:Fluorocarbons / Q000008:administration & dosage*; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology; D008297:Male; D008875:Middle Aged; D009798:Ocular Hypertension / Q000209:etiology* / Q000503:physiopathology; D012189:Retrospective Studies; D014195:Travel; D014821:Vitrectomy / Q000009:adverse effects / Q000379:methods*
chemical_list: D005466:Fluorocarbons