Corneal responses to lens transmissibility

Area of Science:

• Ophthalmology
• Biomedical Engineering
• Optometry

Background:

• Corneal oxygen transmissibility (Dk/L) is crucial for contact lens wear.
• The relationship between Dk/L and corneal relief from hypoxia is complex and non-linear.
• Understanding this relationship is vital for preventing hypoxia-related complications.

Purpose of the Study:

• To investigate and quantify the relationship between lens oxygen transmissibility (Dk/L) and corneal oxygen levels.
• To develop predictive models for corneal response to varying Dk/L values.
• To establish a standardized scale for comparing corneal hypoxic stress.

Main Methods:

• Corneal responses were measured across 28 Dk/L levels, ranging from 1.2 to 189 x 10(-9) (cm/sec)(ml O2/ml mmHg).
• Responses were expressed in oxygen shortfall units (osús) on a relative scale from 0 to 100.
• Data from 11 human corneas were collected and analyzed collectively.

Main Results:

• The relationship between corneal response and Dk/L was found to be monotonic and continuous across the tested range.
• No single equation perfectly described corneal responses across the entire Dk/L spectrum.
• Quadratic equations demonstrated high accuracy (r2 > 0.90) for predicting responses within limited Dk/L domains.

Conclusions:

• The study provides a comprehensive graphical and mathematical description of Dk/L's effect on corneal oxygenation.
• Quadratic equations offer practical tools for laboratory and clinical applications within specific Dk/L ranges.
• These findings aid in optimizing contact lens selection for patient comfort and ocular health.