On the Correlation Between the Curvature of the Human Eyelash and Its Geometrical Features

The study investigated the natural curvature of human eyelashes and found a correlation between the curvature and the geometrical features of the eyelashes. The researchers discovered that, contrary to their expectations, the structural elasticity in bending was greater at the root of the eyelash than at the tip. Upon examining the internal dimensions of the eyelashes' cross sections, they observed that the thickness of the cuticle layer varied between the convex and concave sides at the root, while it remained consistent at the tip. This variation in cuticle thickness displaced the neutral axis, which is central to bending. The study concluded that there is a significant correlation between the displacement of the neutral axis due to the varying cuticle thickness and the curvature of the eyelash. This understanding could potentially lead to methods for artificially controlling eyelash curvature in the future.