Influence of an iris-fixed phakic intraocular lens on the transport of nutrients by the aqueous humor
- 36 Downloads
We study numerically the influence of an iris-fixed phakic intraocular lens (PIOL) on the transport of nutrients by the aqueous humor across a realistic model of the human eye. The Boussinesq equations are solved to calculate the velocity field both in the anterior and posterior chambers. The transport of the nutrient is modeled as that of a passive scalar convected by that velocity field and diffused by the concentration gradient. The nutrient is assumed to be adsorbed at the non-vascularized tissues, i.e., the crystalline lens and cornea endothelium. The adsorption rates at the crystalline and cornea endothelium are supposed to be proportional to the nutrient concentration there. The comparison between the results obtained with and without the PIOL allows us to quantify the influence of this device on the nutrient supply from the aqueous humor. The amount of nutrient adsorbed onto the crystalline is hardly affected by the presence of the PIOL in the anterior chamber, even though there is an iridotomy in this case. When the PIOL is implanted, the flux adsorbed onto the cornea endothelium increases up to around 32% for the highest value of the adsorption coefficient, and hardly varies for the other values of this parameter. This counterintuitive effect is explained by the efficient role played by the iridotomy in evacuating the nutrient from the posterior to the anterior chamber. Based on these results, one can estimate the variation of glucose available in the cornea endothelium after implanting the PIOL, and discuss potential effects on the cell metabolism. These simulations can be regarded as a first attempt to shed light on the mechanisms responsible for the supply of oxygen and glucose to eye avascular structures like the cornea endothelium and crystalline.
KeywordsCFD Aqueous humor flow Intraocular lens Nutrient transport
Partial support from the Junta de Extremadura through Grant No. GR15014 (partially financed by FEDER funds) is gratefully acknowledged.
- Abouali O, Modareszadeh A, Ghaffarieh A, Tu J (2012) Investigation of saccadic eye movement effects on the fluid dynamic in the anterior chamber. J Biomech Eng 134(021):002Google Scholar
- Bert RJ, Caruthers SD, Jara H, Krejza J, Melhem ER, Kolodny NH, Patz S, Freddo TF (2006) Demonstration of an anterior diffusional pathway for solutes in the normal human eye with high spatial resolution contrast-enhanced dynamic MR imaging. Investig Ophthalmol Vis Sci 47:5153–5162CrossRefGoogle Scholar
- Dvoriashyna M, Repetto R, Romano MR, Tweedy JH (2017) Aqueous humour flow in the posterior chamber of the eye and its modifications due to pupillary block and iridotomy. Math Med Biol 0:1–21Google Scholar
- Fernández-Vigo JI, Marcos AC, Agujetas R, Montanero JM, Sánchez-Guillén I, García-Feijóo J, Pandal-Blanco A, Fernández-Vigo JA, Macarro-Merino A (2018) Computational simulation of aqueous humour dynamics in the presence of a posterior-chamber versus iris-fixed phakic intraocular lens. PLoS ONE https://doi.org/10.1371/journal.pone.0202128 CrossRefGoogle Scholar
- Khongar PD, Pralits JO, Cheng X, Pinsky P, Soleri P, Repetto R (2018) Effect of an iris-fixated intraocular lens on corneal metabolism: a numerical study. J Model Ophthalmol 2:97–101Google Scholar
- Repetto R, Pralits JO, Siggers JH, Soleri P (2015) Phakic iris-fixated intraocular lens placement in the anterior chamber: effects on aqueous flow. Cornea 56:3061–3068Google Scholar
- Tweedy JH, Pralits JO, Repetto R, Soleri P (2017) Flow in the anterior chamber of the eye with an implanted iris-fixated artificial lens. Math Med Biol 0:1–23Google Scholar
- Versteeg HK, Malalasekera W (2007) An introduction to computational fluid dynamics. Pearson Education Limited, LondonGoogle Scholar
- Wang W, Qian X, Song H, Zhang M, Liu Z (2016) Fluid and structure coupling analysis of the interaction between aqueous humor and iris. BioMed Eng OnLine 15:569–586Google Scholar