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Rouzbeh Amini, Kole Williams; High Risk of Ocular Hypotony in Patients with Intravitreal Gas Bubbles Traveling through Subsea Tunnels. Invest. Ophthalmol. Vis. Sci. 2016;57(12):4472.
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© ARVO (1962-2015); The Authors (2016-present)
To investigate, using a computational model, the risk of ocular hypotony prompted by trips through subsea tunnels in the presence of intravitreal gas bubbles.
A computational model was developed to simulate intraocular pressure (IOP) changes of eyes with intravitreal gas bubbles during commutes through subsea tunnels. A number of outputs were tracked including bubble size and IOP. Two specific tunnels were modeled: the Seikan Tunnel in Japan and the Bomlafjord Tunnel in Norway. The Seikan Tunnel started at an elevation of 54.2 m and descended to –240 m before returning to 64.2 m. The train traveling through the Seikan Tunnel has an average speed of 140 km/h. The Bomlafjord Tunnel began at an elevation of 45 m, descended to a depth of –260 m, and returned to 10 m above sea level. The Bomlafjord tunnel has an average operating speed of 80 km/h. The computational model incorporated typical traveling rate scenarios through each of these tunnels and used realistic modeling parameters as discussed previously (Retina, 31:1656-1663).
The model predicted a large drop in IOP as patients approached the end of their descent into the tunnel (Fig. 1). An initial IOP of 15 mmHg was assumed for patients before entering each tunnel. Models of both examined tunnels displayed IOP values below 5 mmHg (ocular hypotany) as the patients neared the bottom of the tunnel. Upon exiting the Seikan and Bomlafjord tunnels, the calculated IOP increased from a state of ocular hypotony to 19.46 mmHg and 16.22 mmHg, respectively, before steadily returning to the initial IOP value of 15 mmHg. The gas bubble volume decreased during descent into the tunnel and then returned to its original size following the subsequent ascent. Over the course of each tunnel, the gas bubble volume changed by nearly 1 % (initially filling 70 % of the vitreous cavity).
Based on our simulation, patients with intravitreal gas bubbles may be at increased risk of ocular hypotony while making trips through the modeled subsea tunnels. The bubble size reduction and the subsequent ocular hypotony at low elevation will increase the risk of post-surgical retinal detachment.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
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