## 5 Conclusions  
At physiologically relevant conditions RDA balances the NPL stratum of the \"diseased\" meibum films with sesame oil and the polar lipid stratum of the duplex film with the diverse PL-like molecules present in the eyedrop composition. Consequently, RDA maintains the structure and viscoelastic properties of the MGS duplex multilayer, which are believed to be crucial for the TFLL's ability to restore and maintain the tear film at the ocular surface in vivo during and between blinks [4; 10; 31]. The formulation additionally endeavors to enhance the secretory-mucin-rich gel layer of human tears by incorporating polyvinylpyrrolidone, a polymer that is believed to augment the tear film's shear thinning properties [35; 36; 37; 38; 39; 40]. These properties are crucial for the lubricating action of TF during blinking, as well as for its tensile strength when at interblink [41; 42; 43; 44].  
Overall, the findings support the notion that ophthalmic nanoemulsions are a potentially useful tool for the complex task of soothing the tear film, which is a crucial stage in the treatment of dry eye and other ocular surface diseases [45; 46; 47].  
Supplementary Materials can be found at: [[https://zenodo.org/records/10657564](https://zenodo.org/records/10657564)]([https://zenodo.org/records/10657564](https://zenodo.org/records/10657564)) (accessed on 29 March 2024).  
**Author Contributions:** Conceptualization, G.A.G. and N.Y.; methodology, G.A.G., P.E. and K.T. ([PERSON]); validation, G.A.G., P.E. and N.P.; formal analysis, G.A.G. and P.E.; investigation, P.E., A.S.K. and N.P.; data curation, P.E., A.S.K. and N.P.; writing--original draft preparation, G.A.G., N.Y., K.T. ([PERSON]), K.T. ([PERSON]), M.N. and P.E.; writing--review and editing, G.A.G., N.Y., K.T. ([PERSON]), K.T. ([PERSON]), M.N. and P.E.; visualization, P.E. and N.P.; supervision, G.A.G. and N.Y. All authors have read and agreed to the published version of the manuscript.  
**Funding:** The support of Rohto Pharmaceutical (Osaka, Japan) via a collaborative research grant is gratefully acknowledged. This research was also supported in part by JSPS KAKENHI for Scientific Research from the Japanese Ministry of Education, Culture, Sports, Science and Technology (Grant number: JP20K09794). The research is also partially supported by the Operational Programme \"Science and Education for Smart Growth\" 2014-2020, co-funded by the European Union through the European structural and investment funds, Project BG05M2 OP001-1.002-0019 \"Clean technologies for sustainable environment--water, waste, energy for circular economy\" (Clean&Circle CoC) by the provision of equipment. [PERSON] acknowledges the support of contract P/L 22-1648/ / 07.10.2022 by the Bulgarian Ministry of Education and Science. [PERSON] acknowledges the support of grant by Science Investigations Fund of Sofia University for 2024 year. [PERSON], [PERSON], and [PERSON] are employees of the company. The funding organizations had no role in the design or conduct of this research.  
**Institutional Review Board Statement:** Human meibum samples were collected by Prof. [PERSON] from Kyoto Prefectural University of Medicine in accordance with the tenets of the Declaration of Helsinki and with the permission of the Ethics Committee (IRB approval number ERB-C-1233-4; date: 23 May 2022).  
**Informed Consent Statement:** Informed consent was obtained from all volunteers who donated meibum for biophysical studies.  
**Data Availability Statement:** The raw data supporting the conclusions of this article will be made available by the authors on reasonable request.  
**Acknowledgments:** The support of Rohto Pharmaceutical (Osaka, Japan) via a collaborative research grant, is gratefully acknowledged.  
Conflicts of Interest:Authors [PERSON], [PERSON] and [PERSON] were employed by the company Rohto Pharmaceutical Co., Ltd. The remaining authors declare that the re-search was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.