Modeling the protective role of human eyelashes against ultraviolet light exposure

The role of eyelashes in ocular radiation protection has been hypothesized for some time. There is however no quantitative knowledge of the shading they provide. The ocular protection provided by eyelashes is investigated in this study. A numerical model able to simulate an arbitrary source of light to illuminate a 3-dimensional head model with realistic details was used for this purpose. The eyelashes' filtering effect was studied for various light incidence angles, diameter and density of cilia. Using average values provided by literature to define their characteristics, we found that eyelashes reduce ultraviolet light received by the cornea of about 12-14%, with maximum values of 24%. These results suggest that the eyelashes can be an important element of the human eye protection system and their role should be further investigated.