Oxygen tension measurements: a comparison of methodologies

Area of Science:

• Ophthalmology
• Biomedical Engineering
• Optometry

Background:

• Quantifying oxygen tension under contact lenses is crucial for eye health.
• The equivalent oxygen percentage (EOP) technique and Rasson and Fatt method are common approaches for open-eyelid conditions.
• Variations in contact lens properties may affect oxygen tension measurements.

Purpose of the Study:

• To compare the EOP technique and the Rasson and Fatt method for measuring sub-contact lens oxygen tension.
• To investigate the influence of contact lens center thickness and oxygen transmissibility on these measurements.

Main Methods:

• Five subjects wore six different contact lenses with varying center thicknesses and oxygen transmissibilities.
• Oxygen tension was measured using both the EOP technique and the Rasson and Fatt method for each lens.
• Statistical analysis was performed to compare the results and identify relationships.

Main Results:

• Both methods yielded similar oxygen values for contact lenses with a center thickness of approximately 0.23 mm.
• Significant differences in oxygen values were observed for lenses considerably thicker or thinner than 0.23 mm.
• A strong linear correlation was identified between contact lens center thickness and the ratio of oxygen values obtained by the two methods.

Conclusions:

• The choice of measurement technique for sub-contact lens oxygen tension may be critical, especially for lenses deviating from 0.23 mm center thickness.
• The observed linear relationship provides a potential method for reconciling discrepancies between the two techniques based on lens thickness.