ISO 19979:2018 provides guidance to manufacturers for the development of information to be provided to eye care practitioners for the hygienic management of trial hydrogel, composite and rigid gas-permeable (RGP) contact lenses intended for multipatient use. ISO 19979:2018 does not apply to: - labelling of contact lenses; - the inactivation of prions and viruses since there are no standardised methods available for contact lenses. ISO 19979:2018 can be used as guidance for the development of a hygienic management procedure for multipatient use. NOTE ISO 14729 does not cover multipatient use.