A MODEL FOR THE TEAR FILM AND OCULAR SURFACE TEMPERATURE FOR PARTIAL BLINKS

Area of Science:

• Ophthalmology
• Biophysics
• Fluid Dynamics

Background:

• The tear film is crucial for ocular surface health and vision.
• Partial blinks are common and influence tear film dynamics.
• Understanding tear film behavior is key to diagnosing and treating dry eye disease.

Purpose of the Study:

• To investigate tear film dynamics and temperature variations during partial blinks.
• To elucidate the fluid supply mechanism during partial blink cycles.
• To compare simulated tear film thickness with in vivo measurements.

Main Methods:

• Computational fluid dynamics (CFD) simulations of partial blink cycles.
• Modeling of fluid dynamics and heat transfer within the ocular surface and anterior chamber.
• Comparison of simulation results with in vivo measurements of tear film thickness.

Main Results:

• Varying the fluid layer thickness beneath the upper eyelid improved agreement with in vivo tear film thickness measurements after a half blink.
• Analysis of fluid flux provided an explanation for the observed tear film dynamics.
• Simulations showed rapid readjustment of ocular surface temperature after partial blinks.

Conclusions:

• The thickness of the fluid layer beneath the upper lid is a critical factor in accurately modeling tear film dynamics.
• Partial blinks have a transient but significant impact on tear film thickness and ocular surface temperature.
• The developed model provides insights into the physiological mechanisms governing tear film stability and temperature regulation.