This document provides guidance on the application of all parts of the ISO 11979 series of International Standards for intraocular lenses (IOLs). It addresses factors to be considered in the risk management process of modifications to anterior and posterior chamber IOLs in accordance with ISO 14971. It also suggests methods of data analysis and interpretation that can be used to determine the need for a clinical investigation and its design.nd edition 2017-05 Ophthalmic implants — Intraocular lenses — Guidance on assessment of the need for clinical investigation of intraocular lens design modifications Implants ophtalmiques — Lentilles intraoculaires — Directives relatives à l’évaluation de la nécessité d’investigation clinique pour les modifications de conception des lentilles intraoculaires Reference number ISO/TR 22979:2017(E) ？ ISO 2017 ISO/TR 22979: