Diffusion and Monod kinetics model to determine in vivo human corneal oxygen-consumption rate during soft contact lens wear

Castillo, L. F. del; Silva, Ana R. Ferreira da; Hernández, S. I.; Aguilella, María José Gómez; Andrio, Andreu; Mollá, Sergio; Compañ, Vicente

doi:10.1016/j.optom.2014.06.002

Cited by 8 publications

(41 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…This value represents the oxygen tension when corneal aerobic metabolism reaches its maximum oxygen consumption (that is, oxygen tension needed to achieve equilibrium in the cornea), and the aerobic metabolism reactions of glucose with oxygen (Krebs cycle) is saturated, bringing the system into an oxygen consumption independent of partial pressure. As observed, this model reproduces individual experiments for each lens (Balafilcon and Polymacon lenses), but it could not yield a good solution for both lenses simultaneously, even for two lenses of the same material but with different thicknesses, because the oxygen consumption rate is not the same in all cases.…”

Section: Theoretical Developmentmentioning

confidence: 83%

“…Considering a one‐dimensional model for the cornea (or for any homogeneous slab of oxygen‐consuming tissue), oxygen tension as a function of time and position is given by the equation

\frac{\partial^{2} p_{c}}{\partial x^{2}} - {(\frac{Q}{D k})}_{c} = \frac{1}{D_{c}} \frac{\partial p_{c}}{\partial t}

where p c ( x , t ) is the oxygen partial pressure or tension in the cornea (mmHg), D c is the diffusion coefficient of oxygen in the corneal tissue (cm 2 /sec), k is the oxygen solubility coefficient in the corneal tissue, that is, Henry's law constant (cm 3 of O 2 /cm 3 of tissue/mm of Hg), x is the distance perpendicular to the surface (cm), Q c is the corneal oxygen consumption rate (ml of O 2 /cm 3 of tissue layer/sec), and t is time (s). Subscript c refers to quantities measured at the cornea.…”

Section: Theoretical Developmentmentioning

confidence: 99%

“…Del Castillo et al recently showed that the corneal oxygen consumption rate Q c decreases as the oxygen pressure p c decreases in the post‐lens tear interface. Bonanno et al observed that both corneal oxygen flux and oxygen consumption Q c increase when post‐lens tear oxygen tension increases when several contact lenses of different oxygen transmissibility are worn reaching higher levels than those expected based on previous in vitro corneal measurements.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Analysis of the application of the generalized monod kinetics model to describe the human corneal oxygen‐consumption rate during soft contact lens wear

et al. 2016

View full text Add to dashboard Cite

This work is an analysis of the application of the generalized Monod kinetics model describing human corneal oxygen consumption during soft contact lens wear to models previously used by Chhabra et al. (J Biomed Mater Res B Appl Biomater, 2009a;90:202-209, Optom Vis Sci 2009b;86:454-466) and Larrea and Büchler (Invest Ophthalmol Vis Sci 2009;50:1076-1080). We use oxygen tension from in vivo estimations provided by Bonanno [Bonanno et al., Invest Ophthalmol Vis Sci 2002;43:371-376, and Bonanno et al 2009]. We consider four hydrogel and six silicone hydrogel lenses. The cornea is considered a single homogeneous layer, with constant oxygen permeability regardless of the type of lens worn. Our calculations yield different values for the maximum oxygen consumption rate Q , whith differents oxygen tensions (high and low p ) at the cornea-tears interface. Surprisingly, for both models, we observe an increase in oxygen consumption near an oxygen tension of 105 mmHg until a maximum is reached, then decreasing for higher levels of oxygen pressure. That is, when lowering the pressure of oxygen, the parameter Q initially increases depending on the intensity of the change in pressure. Which, it could be related with the variation of the pH. Furthermore, it is also noted that to greater reductions in pressure, this parameter decreases, possibly due to changes in the concentration of glucose related to the anaerobic respiration. The averaged in vivo human corneal oxygen consumption rate of 1.47 × 10 cm of O /cm tissue s, with Monod kinetics model, considering all the lenses studied, is smaller than the average oxygen consumption rate value obtained using the Larrea and Büchler model. The impact that these calculations have on the oxygen partial pressure available at different depths in the corneal tissue is presented and discussed, taking into consideration previous models used in this study. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 2269-2281, 2017.

show abstract

Section: Theoretical Developmentmentioning

confidence: 83%

“…Considering a one‐dimensional model for the cornea (or for any homogeneous slab of oxygen‐consuming tissue), oxygen tension as a function of time and position is given by the equation

\frac{\partial^{2} p_{c}}{\partial x^{2}} - {(\frac{Q}{D k})}_{c} = \frac{1}{D_{c}} \frac{\partial p_{c}}{\partial t}

Section: Theoretical Developmentmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Analysis of the application of the generalized monod kinetics model to describe the human corneal oxygen‐consumption rate during soft contact lens wear

et al. 2016

View full text Add to dashboard Cite

show abstract

“…Experimental data have also demonstrated that lateral diffusion is minimal. Considering the cornea as a one‐dimensional homogenous tissue, the non‐steady‐state equation for the oxygen pressure as a function of time and position is given by the equation

D_{c} \frac{\partial^{2} p_{c}}{\partial x^{2}} - \frac{Q ((), p_{normalc})}{k_{normalc}} = \frac{\partial p_{c}}{\partial t}

where p c ( x , t ) is the oxygen tension in the cornea (in mmHg), D c is the oxygen diffusion coefficient into the cornea, k c is the oxygen solubility coefficient in the corneal tissue (cm 3 of O 2 /cm 3 of tissue/mmHg), x is the distance perpendicular to the surface (in cm), Q ( p c ) is the oxygen consumption rate (mL of O 2 /cm 3 of tissue layer/s), and t is time (in s). The subscript c refers to the quantities measured at the cornea.…”

Section: Methodsmentioning

confidence: 99%

“…Recently, various researchers have presented a Monod model of time‐dependent oxygen diffusion in the cornea . Michaelis–Menten‐type relationship for oxygen uptake kinetics was used to complete this model . The experimental data of Bonanno et al were used to validate the model and to determine the oxygen consumption and diffusivity of the cornea by fitting the model to different cases of CL transmissibility.…”

Section: Introductionmentioning

confidence: 99%

Corneal relaxation time estimation as a function of tear oxygen tension in human cornea during contact lens wear

et al. 2019

Self Cite

View full text Add to dashboard Cite

The purpose is to estimate the oxygen diffusion coefficient and the relaxation time of the cornea with respect to the oxygen tension at the cornea–tears interface. Both findings are discussed. From the experimental data provided by Bonanno et al., the oxygen tension measurements in vivo for human cornea–tears–contact lens (CL), the relaxation time of the cornea, and their oxygen diffusion coefficient were obtained by numerical calculation using the Monod‐kinetic model. Our results, considering the relaxation time of the cornea, observe a different behavior. At the time less than 8 s, the oxygen diffusivity process is upper‐diffusive, and for the relaxation time greater than 8 s, the oxygen diffusivity process is lower‐diffusive. Both cases depend on the partial pressure of oxygen at the entrance of the cornea. The oxygen tension distribution in the cornea–tears interface is separated into two different zones: one for conventional hydrogels, which is located between 6 and 75 mmHg, with a relaxation time included between 8 and 19 s, and the other zone for silicone hydrogel CLs, which is located at high oxygen tension, between 95 and 140 mmHg, with a relaxation time in the interval of 1.5–8 s. It is found that in each zone, the diffusion coefficient varies linearly with the oxygen concentration, presenting a discontinuity in the transition of 8 s. This could be interpreted as an aerobic‐to‐anaerobic transition. We attribute this behavior to the coupling formalism between oxygen diffusion and biochemical reactions to produce adenosine triphosphate. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 108B:14–21, 2020.

show abstract

Athree‐dimensionalmodel to describe complete human corneal oxygenation during contact lens wear

Aguilella‐Arzo

Compañ

2022

J Biomed Mater Res

Self Cite

View full text Add to dashboard Cite

We perform a novel 3D study to quantify the corneal oxygen consumption and diffusion in each part of the cornea with different contact lens materials. The oxygen profile is calculated as a function of oxygen tension at the cornea-tear interface and the oxygen transmissibility of the lens, with values used in previous studies. We aim to determine the influence of a detailed geometry of the cornea in their modeling compared to previous low dimensional models used in the literature. To this end, a 3-D study based on an axisymmetric volume element analysis model was applied to different contact lenses currently on the market. We have obtained that the model provides a valuable tool for understanding the flux and cornea oxygen profiles through the epithelium, stroma, and endothelium. The most important results are related to the dependence of the oxygen flux through the cornea-lens system on the contact lens thickness and geometry. Both parameters play an important role in the corneal flux and oxygen tension distribution.The decline in oxygen consumption experienced by the cornea takes place just inside the epithelium, where the oxygen tension falls to between 95 and 16 mmHg under open eye conditions, and 30 to 0.3 mmHg under closed eye conditions, depending on the contact lens worn. This helps to understand the physiological response of the corneal tissue under conditions of daily and overnight contact lens wear, and the importance of detailed geometry of the cornea in the modeling of diffusion for oxygen and other species. 3-D model, corneal oxygen distribution, corneal oxygen flux, Monod kinetics model, oxygen tension, soft contact lens | INTRODUCTIONThe subject of the oxygen demand of a human cornea has received a great deal of attention in recent years, and has been the subject of an extensive debate, with many models appearing, aiming to explain the distribution of oxygen consumption, the profile of partial pressure of oxygen, and the flux though the entire cornea (epithelium, stroma and endothelium).Most models carry out their study assuming a 1D geometry for the oxygen transport through the cornea/tear/lens system. 1-6 Some of the models assume a constant thickness and oxygen consumption, and they have evolved considering different multilayers for the cornea/tear/lens system as a mono-dimensional model. 3,4,[7][8][9][10] However, the first models considered a constant corneal oxygen consumption rate in which the diffusion equation was treated only as steady, and not as time-dependent. 5,[11][12][13][14][15] Negative values of the partial pressure

show abstract

Diffusion and Monod kinetics model to determine in vivo human corneal oxygen-consumption rate during soft contact lens wear

Abstract: Present results are relevant for the calculation on the partial pressure of oxygen, available at different depths into the corneal tissue behind contact lenses of different oxygen transmissibility.

Cited by 8 publications

References 15 publications

Analysis of the application of the generalized monod kinetics model to describe the human corneal oxygen‐consumption rate during soft contact lens wear

Analysis of the application of the generalized monod kinetics model to describe the human corneal oxygen‐consumption rate during soft contact lens wear

Corneal relaxation time estimation as a function of tear oxygen tension in human cornea during contact lens wear

Athree‐dimensionalmodel to describe complete human corneal oxygenation during contact lens wear

Contact Info

Product

Resources

About