IEC 61280-2-2:2012 describes a test procedure to verify compliance with a predetermined waveform mask and to measure the eye pattern and waveform parameters such as rise time, fall time, modulation amplitude and extinction ratio. This fourth edition cancels and replaces the third edition published in 2008 and constitutes a technical revision .This edition includes the following significant technical changes with respect to the previous edition: additional definitions, clarification of test procedures. Keywords: optical eye pattern, waveform, modulation amplitude, extinction ratio The contents of the corrigendum of February 2015 have been included in this copy.