A process for destroying a DNA or RNA of a microorganism on a substance or surface comprising the steps of: generating photons of at least one wavelength corresponding to a peak absorption wavelength of DNA or RNA, the at least one wavelength being at least one of 222 nm and 282 nm; directing the photons to a substance or surface to be disinfected, whereby the photons are selected to destroy a plurality of chemical bonds within the DNA or RNA of the microorganisms; and wherein the substance or surface to be disinfected is an eye tissue.