title: Computational simulation of altitude change-induced intraocular pressure alteration in patients with intravitreal gas bubbles.
abstract: OBJECTIVE
  To study the impact of altitude on the intraocular pressure (IOP) in an eye with an intravitreal gas bubble.
  
  
  METHODS
  A mathematical model was developed to simulate intravitreal gas bubble expansion caused by change in altitude. Mechanical deformation of the eye was simulated using a finite-element model. Intraocular pressure-driven changes in aqueous humor flow were also considered. Two cases were studied: 1) ascent from sea level to 3,000 ft followed by immediate return to sea level and 2) ascent to 3,000 ft followed by prolonged exposure to 3,000 ft. The effect of IOP-lowering medications was studied by changing the model parameters.
  
  
  RESULTS
  The IOP increase was directly related to the initial bubble size when ascent to 3,000 ft was simulated. When prolonged exposure to high altitude was modeled, loss of aqueous humor led to a less elevated value of IOP. In a typical simulated case, when the outflow facility was increased, the predicted IOP rise was reduced by 28%.
  
  
  CONCLUSIONS
  Theoretical modeling of an eye with an intravitreal gas bubble can help an ophthalmologist evaluate the impact of altitude-induced IOP changes. Our model suggests that IOP-lowering drugs could help manage altitude-induced IOP changes in the presence of intravitreal gas bubbles.
authors.affiliation: Department of Biomedical Engineering, University of Minnesota, Minneapolis, Minnesota 55455, USA. amin0035@umn.edu
authors.forename: Rouzbeh
authors.initials: R
authors.lastname: Amini
authors.forename: Victor H
authors.initials: VH
authors.lastname: Barocas
authors.forename: H Pirouz
authors.initials: HP
authors.lastname: Kavehpour
authors.forename: Jean Pierre
authors.initials: JP
authors.lastname: Hubschman
mesh_terms: D000531:Altitude; D001082:Aqueous Humor / Q000378:metabolism; D003198:Computer Simulation; D003315:Cornea / Q000502:physiology; D004548:Elasticity / Q000502:physiology; D005128:Eye Diseases / Q000378:metabolism*; D020342:Finite Element Analysis; D005740:Gases; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology*; D008962:Models, Theoretical; D012590:Sclera / Q000502:physiology; D014822:Vitreous Body / Q000378:metabolism*
chemical_list: D005740:Gases