title: An assessment of intraocular pressure rise in patients with gas-filled eyes during simulated air flight.
abstract: OBJECTIVE
  To investigate the safety of aircraft flight for patients with small volumes of residual postoperative intraocular gas.
  
  
  METHODS
  Nonrandomized comparative trial.
  
  
  METHODS
  Seventeen eyes (nine gas filled and eight control eyes) of nine patients and one eye of one control subject were tested.
  
  
  METHODS
  Patients with postoperative intraocular gas and the control subject were tested in the controlled environment of a hypobaric chamber to simulate the cabin depressurization associated with a typical commercial aircraft flight. Before, during, and after a simulated flight, the intraocular pressure (IOP) in the gas-containing and contralateral eyes was tested using the Perkins (Edinburgh, UK) and Tono-Pen XL (Jacksonville, FL) tonometers.
  
  
  METHODS
  The absolute and percentage change in IOP with varied cabin pressurization.
  
  
  RESULTS
  Of the nine patients with intraocular gas, seven had 10% to 15% gas volume and two had 20% gas volume. In the 10% to 15% gas volume group, the IOP rose by an average of 109% from baseline during ascent to an average cabin altitude of 7429 feet above sea level. The IOP dropped to an average of 30% above baseline IOP during the cruise phase and further decreased to an average of 38% below baseline IOP on return to baseline altitude. In the 20% gas volume group, the IOP rose by an average of 84% from baseline during ascent to an average cabin altitude of 3400 feet above sea level. The IOP dropped to an average of 42% below baseline IOP on return to baseline altitude. The IOP in the contralateral control eyes did not vary with altitude changes. No patient experienced pain or visual loss during the experiments.
  
  
  CONCLUSIONS
  Our results demonstrate that IOP may rise significantly in gas-filled eyes during simulated air flight, supporting the current conservative recommendation against air travel for most patients with intraocular gas bubbles. Further testing is warranted to develop a more objective measure of intraocular gas volume estimation and to define better the tolerability of aircraft flight for patients with intraocular gas.
authors.affiliation: Department of Ophthalmology, University of Toronto, Toronto, Ontario, Canada.
authors.forename: M D
authors.initials: MD
authors.lastname: Mills
authors.forename: R G
authors.initials: RG
authors.lastname: Devenyi
authors.forename: W C
authors.initials: WC
authors.lastname: Lam
authors.forename: A R
authors.initials: AR
authors.lastname: Berger
authors.forename: C D
authors.initials: CD
authors.lastname: Beijer
authors.forename: S R
authors.initials: SR
authors.lastname: Lam
mesh_terms: D000328:Adult; D000337:Aerospace Medicine; D000368:Aged; D000369:Aged, 80 and over; D000401:Aircraft; D004780:Environment, Controlled; D005260:Female; D005466:Fluorocarbons / Q000627:therapeutic use*; D006801:Humans; D007429:Intraocular Pressure; D008297:Male; D008875:Middle Aged; D009798:Ocular Hypertension / Q000209:etiology*; D012163:Retinal Detachment / Q000601:surgery; D012167:Retinal Perforations / Q000601:surgery; D013459:Sulfur Hexafluoride / Q000627:therapeutic use*; D014821:Vitrectomy; D014822:Vitreous Body
chemical_list: D005466:Fluorocarbons; C042852:perflutren; D013459:Sulfur Hexafluoride