Oxygen kinetics during corneal crosslinking with and without supplementary oxygen.

Seiler, Theo G.; Komninou, Maria Angeliki; Nambiar, Malavika H.; Schürch, Kaspar; Frueh, Beatrice E.; Büchler, Philippe (2021). Oxygen kinetics during corneal crosslinking with and without supplementary oxygen. American journal of ophthalmology, 223, pp. 368-376. Elsevier Science 10.1016/j.ajo.2020.11.001

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PURPOSE

To measure and simulate oxygen kinetics during corneal crosslinking (CXL) at different irradiances with and without supplementary oxygen.

DESIGN

Experimental, laboratory study.

METHODS

In de-epithelialized porcine eyes, a femtosecond-laser generated tunnel was used to place a fiber-probe in corneal depths of 100, 200 and 300μm to measure the local oxygen concentration. After riboflavin imbibition, the corneas were irradiated at 3, 9, 18 and 30mW/cm2 while the oxygen concentration was measured. All experiments were performed under normoxic (21%) and hyperoxic (>95%) conditions. The obtained data were used to identify parameters of a numerical model for oxygen consumption and diffusion.

RESULTS

The equilibrium stromal oxygen concentration under atmospheric oxygen at 3mW/cm2 was 2.3% in 100μm decreasing to <1% in 300μm. With 9, 18 and 30mW/cm2, no oxygen was available in 200μm respectively 100μm or deeper. Using a hyperoxic environment, the concentration was 50% using 3mW/cm2 in 100μm, decreasing to 40% in 300μm. At 9mW/cm2 the concentrations were 5%, 3% and 1% in 100, 200 and 300μm, respectively. Using 18 and 30mW/cm2 all oxygen was depleted at 100μm, however, oxygen half-lives were longer at 18mW/cm2 than at 30mW/cm2. The oxygen model was able to reproduce the experiments and indicated an exponential decay with increasing distance to the anterior surface.

CONCLUSION

Supplementary oxygen increases the oxygen-availability during CXL. At higher irradiances, supplementary oxygen is beneficial and eliminates the bottleneck of oxygen allowing a potentially more efficient crosslinking. The calibrated numerical model can quantify the spatial oxygen concentration related to different scenarios such as irradiance or environmental oxygen concentration.

Item Type:

Journal Article (Original Article)

Division/Institute:

10 Strategic Research Centers > ARTORG Center for Biomedical Engineering Research > ARTORG Center - Musculoskeletal Biomechanics
04 Faculty of Medicine > Department of Head Organs and Neurology (DKNS) > Clinic of Ophthalmology
10 Strategic Research Centers > ARTORG Center for Biomedical Engineering Research

Graduate School:

Graduate School for Cellular and Biomedical Sciences (GCB)

UniBE Contributor:

Seiler, Günter Theodor Michael; Komninou, Maria Angeliki; Nambiar, Malavika Harikrishnan; Schürch, Kaspar Werner; Früh Epstein, Beatrice and Büchler, Philippe

Subjects:

600 Technology > 610 Medicine & health
500 Science > 570 Life sciences; biology
600 Technology > 620 Engineering

ISSN:

0002-9394

Publisher:

Elsevier Science

Language:

English

Submitter:

Philippe Büchler

Date Deposited:

25 Jan 2021 11:24

Last Modified:

21 Mar 2021 01:34

Publisher DOI:

10.1016/j.ajo.2020.11.001

PubMed ID:

33227242

Uncontrolled Keywords:

CXL Cornea Cross-linking Crosslinking Kinetics Oxygen

BORIS DOI:

10.48350/150681

URI:

https://boris.unibe.ch/id/eprint/150681

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