Equilibrium shape of the aqueous humor-vitreous substitute interface in vitrectomized eyes

Krystyna Isakova, Jan O. Pralits, Mario R. Romano, Jan-Willem M. Beenakker, Denis P. Shamonin, Rodolfo Repetto

Abstract


Purpose: To predict the shape of the interface between aqueous humor and a tamponade, gas or silicone oil (SO), in vitrectomized eyes. To quantify the tamponated retinal surface for various eye shapes, from emmetropic to highly myopic eyes.

Methods: We use a mathematical model to determine the equilibrium shape of the interface between the two fluids. The model is based on the VOF (volume of fluids) method. The governing equations are solved numerically using the free software OpenFOAM. We apply the model both to the case of idealized, yet realistic, geometries of emmetropic and myopic eyes and to a real geometry reconstructed from MRI images of the vitreous chamber.

Results: The numerical model allows us to compute the equilibrium shape of the interface between the aqueous humor and the tamponade fluid. From this we can compute the portion of the retinal surface that is effectively tamponated by the fluid. We compare the tamponating ability of gases and SOs. We also compare the tamponating effect in emmetropic and myopic eyes by computing both tamponated area and angular coverage.

Conclusion: The numerical results show that gases have better tamponating properties than SOs. We also show that, for a given filling ratio the percentage of tamponated retinal surface area is smaller in myopic eyes. The method is valuable for clinical purposes, especially in patients with pathological eye shapes, to predict the area of the retina that will be tamponated for a given amount of injected fluid.


Keywords


vitrectomy, tamponade fluids, surface tension, interface

Full Text:

PDF

References


Scott JD. Prevention and perspective in retinal detachment. Eye 1989;3:491–515. doi: 10.1038/eye.1989.82.

Romano MR, Das R, Groenwald C, Stappler T, Marticorena J, Valldeperas X, et al. Primary 23- gauge sutureless vitrectomy for rhegmatogenous retinal detachment. Indian journal of ophthalmology 2012;60(1):29-33. doi: 10.4103/0301-4738.90487.

D’Amico DJ. Primary retinal detachment. New England Journal of Medicine, 2008;359:2346– 2354. doi: 10.1056/NEJMcp0804591.

Oster SF, Mojana F, Bartsch DUG, Goldbaum M, Freeman, WR. Dynamics of the macular hole- silicone oil tamponade interface with patient positioning as imaged by spectral domain optical coherence tomography. Retina 2010;30(6):924-929. doi: 10.1097/IAE.0b013e3181c96a6c

Fawcett IM, Williams RL, Wong D. Contact angles of substances used for internal tamponade in retinal detachment surgery. Graefe’s Arch Clin Exp Ophthalmol 1994;232:438–444. doi: 10.1007/BF00186587

Eames I, Angunawela RI, Aylward GW, et al. A theoretical model for predicting interfacial relationships of retinal tamponades. Investigative Ophtalmology & Visual Science 2010;51(4):2243–2247. doi: 10.1167/iovs.09-4442.

Pozrikidis C, Gartling DK. Fluid Dynamics: Theory, Computation, and Numerical Simulation. Applied Mechanics Reviews. 2002;55:B55.

Spandau U, Heinmann H. Practical Handbook for Small-Gauge Vitrectomy. A step-by-step introduction to surgical techniques, volume XIX. Springer, 2012. doi: 10.1007/978-3-642-23294-7.

Joussen AM, Wong D. The concept of heavy tamponades-chances and limitations. Graefe’s Arch

Clin Exp Ophthalmol 2008;246:1217–1224. doi: 10.1007/s00417-008-0861-0.

Deshpande SS, Anumolu L, Trujillo MF. Evaluating the performance of the two-phase flow solver

interfoam. Computational science & discovery 2012;5:1749–4699. doi:10.1088/1749-

/5/1/014016.

Hirt CW, Nichols BD. Volume of fluid (VOF) method for the dynamics of free boundaries. Journal

of computational physics 1981;39(1):201–225. doi:10.1016/0021-9991(81)90145-5

http://openfoam.com.

Atchison DA, Smith G. Optics of the human eye. Butterworth-Heinemann 2000. Available from:

https://www.elsevier.com/books/optics-of-the-human-eye/atchison/978-0-7506-3775-6

Atchison DA, Jones CE, Schmid KL, et al. Eye shape in emmetropia and myopia. Investigative

Ophthalmology & Visual Science 2004;45:3380–3386. doi:10.1167/iovs.04-0292.

Beenakker JWM, van Rijn G, Luyten GPM, et al. High resolution MRI of uveal melanoma using a

microcoil phased array at 7 T. NMR Biomed, 2013;26(12):1864-1869. doi: 10.1002/nbm.3041

Beenakker JWM, Shamonin DP, Webb AG, Luyten GPM, Stoel BC. Automated retinal topographic maps measured with magnetic resonance imaging. Investigative Ophthalmology & Visual Science,

;56:1033–1039. doi:10.1167/iovs.14-15161.

Berkowitz BA. MRI of retinal and optic nerve physiology. NMR in Biomedicine, 2008;21(9):927–

doi: 10.1002/nbm.1275.

Wong D, Van Meurs JC, Stappler T, Groenewald C, Pearce IA, McGalliard JN, et al. A pilot study

on the use of a perfluorohexyloctane/silicone oil solution as a heavier than water internal tamponade agent. British journal of ophthalmology 2005;89:662–665. doi: 10.1136/bjo.2004.055178

Hillier RJ, Stappler T, Williams RL, et al. The impact of axial length on retinal tamponade for gas, silicone oil, and heavy silicone oil, using an in vitro model. Graefe’s Arch Clin Exp Ophthalmol 2011;249:671–675. doi: 10.1007/s00417-010-1579-3


Refbacks

  • There are currently no refbacks.


Copyright (c) 2017 Journal for Modeling in Ophthalmology