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R. Amini, V. H. Barocas, H. P. Kavehpour, J.-P. Hubschman; Computational Simulation of Intraocular Pressure Rise Caused by Intravitreal Gas Expansion During Altitude Changes. Invest. Ophthalmol. Vis. Sci. 2010;51(13):3588.
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© ARVO (1962-2015); The Authors (2016-present)
To study by using a computational model how altitude variation increases the intraocular pressure (IOP) due to intravitreal gas expansion.
A mathematical model was developed to simulate expansion of gas bubbles injected into the vitreous cavity according to altitude variations. A finite element model of the corneoscleral shell was used to simulate the mechanical deformation of the eye globe. IOP-driven changes in aqueous humor flow were also incorporated in the mathematical model. Two cases were modeled. First, ascending to 3000 ft and returning back to the sea level was modeled based on published experiments. Second, ascending to 3000 ft and staying at high altitude indefinitely was simulated. The effects of initial bubble volume as well as the effect of medication lowering intraocular pressure were analyzed in a series of parametric studies.
When elevation to 3000 ft was simulated, IOP rose to 48.5 mmHg (initial gas volume filled 65% of the vitreous cavity). When prolonged exposure to high altitude was simulated, IOP eventually returned to a lower value due to loss of aqueous humor. The larger the initial bubble was, the higher the IOP increase was. When the outflow facility was increased, a limited rise in the IOP only up to 24.9 mmHg was predicted.
Our model prediction was consistent with the published experimental data. Based on our simulation, using medications that increase the aqueous humor outflow facility or decrease the aqueous humor secretion rate may be helpful in managing the IOP changes in patients with intravitreal gas bubbles.
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