A Detailed Molecular Model of the Tear Film Lipid Layer

The tear film lipid layer (TFLL) is an outermost component of the tear film. The TFLL plays a critical role in maintaining ocular hydration, protecting the corneal surface, and preserving visual clarity. By stabilizing the tear film and minimizing evaporative water loss, the TFLL helps to prevent tear film breakup. Disruptions in the structural organization or chemical composition of the TFLL can compromise its function and cause dry eye disease (DED). Molecular-level mechanisms governing the TFLL behavior remain poorly understood. This study presents large-scale, atomistic molecular dynamics (MD) simulations of TFLL incorporating physiological lipid compositions. Model accuracy was validated by comparison to previously reported experimental properties. The model exhibited reasonable densities and lipid ordering, as previously observed in spectroscopic studies. Shear thinning behavior was observed, consistent with known viscoelastic characteristics. Lateral diffusion coefficients were in reasonable agreement with experimental data. The resulting atomistic representation is a reproducible, high-resolution molecular model that will enable future investigations into TFLL properties. The model structure provides mechanistic insights into tear film structuring and establishes a foundation for future computational work that can inform the development of more effective, long-lasting therapies for DED.