Oxygen transfer in the human cornea: Sensitivity and error-propagation analyses incorporating an...

Area of Science:

• Ophthalmology
• Biomedical Engineering
• Corneal Physiology

Background:

• Eye diseases and contact lens wear reduce corneal oxygen diffusion, vital for eye metabolism.
• Accurate measurement of corneal oxygen diffusion is challenging due to the cornea's thinness and need for viability.
• Current models often assume a constant diffusion coefficient, despite evidence of oxygen-tension dependence.

Purpose of the Study:

• To investigate corneal oxygen diffusion using an oxygen-tension-dependent model.
• To refine the extraction of corneal properties by bounding the maximum oxygen consumption rate.
• To analyze the impact of measurement errors on extracted corneal properties.

Main Methods:

• An in vivo technique using a photosensitive dye-coated contact lens to measure oxygen tension via phosphorescence quenching.
• Development and application of a diffusion model incorporating an oxygen-tension-dependent diffusion coefficient.
• Sensitivity and error-propagation analyses to quantify the impact of measurement uncertainties.

Main Results:

• The oxygen-tension dependence of the diffusion coefficient is significant and cannot be neglected.
• A small error (2.6%) in oxygen tension measurement can lead to a large error (76%) in the diffusion coefficient.
• Narrow bounds were placed on the maximum oxygen consumption rate, reducing the number of extractable properties.

Conclusions:

• The oxygen-tension dependence of corneal diffusion is critical and requires accurate modeling.
• Minimizing measurement errors through replicate experiments and improved analytical techniques is essential for reliable corneal property extraction.
• This study provides a more robust method for assessing corneal oxygen transport, crucial for understanding eye health and disease.