Eyelashes keep vision clear by actively repelling water
Throughout human evolution, the presence of body and facial hair has diminished. Yet, eyelashes have remained a distinctive feature.
Traditionally, their role has been considered purely protective – catching dust, filtering air and water, and aiding in vision. However, the functional purpose of eyelashes has remained the subject of debate.
A recent study by Chinese researchers has unveiled fascinating insights into the role and structure of human eyelashes.
Conducted by Professor Jiang Lei and his team from the Technical Institute of Physics and Chemistry of the Chinese Academy of Sciences, the research highlights the hydrodynamic advantages of eyelashes in maintaining visual clarity.
The team examined the sophisticated design and functionality of these small yet vital features.
What makes eyelashes unique?
The study revealed that eyelashes consist of a hydrophobic, curved, and flexible fiber array. The fibers feature surface micro-ratchets and a macro-curvature resembling the Brachistochrone curve.
This unique structure enables eyelashes to expel liquid rapidly and directionally, ensuring clear vision even in challenging conditions.
Eyelashes are not merely for aesthetic appeal or shielding the eyes from debris. The study highlighted that eyelashes actively repel water, a feature that has been largely overlooked in scientific literature.
Eyelashes repel water
The team investigated the interaction between water and the flexible fiber array of eyelashes. The study carefully examined the unique design of human eyelashes, focusing on three main aspects:
- Structure: the physical arrangement of the eyelash fibers, including their curvature and alignment.
- Wettability: how easily water interacts with or slides off the surface of eyelashes.
- Water Drainage: the process through which water is moved away from the eyes by the eyelashes.
The researchers also investigated how the flexibility, shape (curvature), and elasticity (ability to stretch and return to shape) of eyelashes contribute to their effectiveness in repelling water. These features help eyelashes function as a natural barrier against liquid.
The results of the study led to some key conclusions:
Hydrophobic and curved design
Eyelashes repel water because of their water-resistant surface and curved structure. This design directs water away from the eyes, keeping them dry.
Asymmetric structures and elasticity
The varying shapes and elastic properties of the eyelashes control how liquid moves around. These properties determine the direction in which water flows and how long it stays in contact with the eyelashes.
Computational modeling
The team developed a mathematical model to measure the forces acting on the eyelashes. This helped explain why they quickly push water away.
These mechanisms ensure that during daily activities like washing your face or sweating, eyelashes prevent water from entering the eyes. This allows for clear vision, even in wet conditions.
Broader applications of eyelash research
The implications of this research extend beyond understanding human anatomy. The findings have inspired the design of certain innovative technologies.
Water repellent false eyelashes
Water repellent false eyelashes are designed to replicate the natural properties of human eyelashes. Not only are they visually appealing, but they also provide a functional benefit by repelling water, similar to natural eyelashes.
This makes them practical for use in wet environments, enhancing both aesthetics and protection.
Waterproof imaging devices
The study’s findings inspired the creation of imaging devices that mimic the structure of eyelashes. The devices use similar water-repelling designs that improve their functionality and performance in wet or humid conditions.
This innovation can benefit fields like underwater photography or outdoor surveillance.
Ventilated structures
By applying the design principles of eyelashes, researchers have developed structures that manage air and liquid flow effectively.
These can be used in various applications, such as building ventilation systems or equipment that requires controlled airflow and moisture resistance, and ensures better efficiency and durability.
Professor Jiang’s team emphasized that their work bridges biological understanding with practical applications, showcasing how nature’s designs can inspire advanced technologies.
Additional eye hygiene tips
While eyelashes play a crucial role in protecting eyes from liquid and debris, maintaining proper eye hygiene is equally important. The NHS recommends:
- washing hands before and after touching the eyes,
- cleaning glasses regularly, and
- avoiding sleeping in contact lenses.
These practices can prevent dirt and bacteria from entering the eyes, thus reducing the risk of infections.
Water-repelling potential of eyelashes
In conclusion, eyelashes are more than just a facial feature; they are a sophisticated natural mechanism designed to protect and maintain visual clarity.
The study from the Chinese Academy of Sciences sheds light on their unique structure and functionality, revealing a deeper appreciation for these seemingly simple fibers.
The study is published in the journal Science Advances.
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