A group of researchers in China tried to find some scientific basis of this claimed property of lead sulphide (galena) relating to absorption of sun rays when applied into the eyes in the form of kohl.[23] The authors reported the ultraviolet (UV) absorption spectra of a thin film of lead sulphide prepared on "Indium Tin Oxide" (ITO) substrate. The spectra showed that lead sulphide thin films had higher absorption and lower transmittance in UV light band which further increases with the increased deposition voltage.

In January 2010, French researchers reported that the particular heavy eye makeup that ancient Egyptians wore may have had medical benefits. At submicromolar concentrations, the specially made lead compounds can elicit overproduction of nitrous oxide (N2O), which in turn can trigger an enhancement of the immune response.[32][33]

The ancient Egyptians, documented in the Ebers Papyrus (c. 1550 BCE), discuss these compounds within kohl as protective for the eyes.