In vitro biophysical and biological profiling of commercial lipid-based dry eye products

There is an increasing number of products available for treatment of dry eye disease (DED), thereby creating a challenge in selecting a suitable product. Commercial products have rarely been studied in the same experimental setup, and in the case of lipid-based products, their baseline capabilities to target central defects of DED requires a more thorough investigation. This study aims to discern potential differences in their abilities to stabilize the tear film, reduce the evaporation of water, and impact on corneal epithelial cell viability and recovery utilizing various biophysical and biological in vitro techniques. Seven commercial lipid-based eye drops (Cationorm®, Desodrop®, Evotears®, Oxyal® Triple Action, Puro™ Suoja, Systane® Complete, Thealipid®) were selected for the in vitro biophysical and biological profiling studies. Biophysical properties critical for tear film stability and evaporation reduction were evaluated using Langmuir trough techniques, while cell viability and recovery were assessed by an MTT assay after exposing either healthy or damaged human corneal epithelial cells to the products. The majority of the products spread reasonably well at the aqueous-air interface, suggesting that they bear intrinsic properties which may be beneficial to improving the coverage of the tear film lipid layer. However, only subtle evaporation reduction capabilities were observed, indicating that the products are not optimal at targeting this defect. Clear differences in cell viability and recovery were observed, with three of the products being able to promote the recovery of damaged cells. The significance of our findings with regards to DED treatment outcomes will require additional studies in the future.