Introduction

The pattern electroretinogram (PERG) is a retinal biopotential that is evoked when a temporally modulated patterned stimulus of constant total luminance (checkerboard or grating) is viewed. The PERG is most often evoked by alternating reversal of a checkerboard pattern. It may be altered in dysfunction of the macula or of the inner retina selectively, which do not significantly affect the conventional full-field ERG. The PERG receives clinical and research attention in both neurological and ophthalmological practice. However, the PERG is a very small signal, typically in the region of 0.5–8µV depending on stimulus characteristics, and PERG recording is technically more demanding than the conventional ERG. Recordings published in the literature vary considerably in technical quality as well as technique, and new users may find it difficult to choose which technique to use.

The International Society for Clinical Electrophysiology of Vision (ISCEV) feels that there is now a sufficient body of knowledge and clinical experience to propose a standard for performing a basic PERG. This document evolved from the “PERG Guidelines”¹ and is intended as a guide to practice and to assist in interpretation of PERGs. Transient PERG as described below represents the minimum of what a PERG evaluation should include. The standard describes simple technical procedures that allow reproducible PERGs to be recorded under a few defined conditions. Different procedures may provide equivalent PERG responses. It is incumbent on users of alternative techniques to demonstrate that their procedures do in fact produce signals that are equivalent in basic waveform, amplitude, and physiologic significance to the standard. Our intention is that the standard method and responses be used widely, but not to the exclusion of other paradigms that individual laboratories may use, tailored to their own requirements.

The standard is based upon equipment and analytic capabilities currently found in most neurophysiological or ophthalmological electrodiagnostic clinics. This document addresses recording conditions and technology specific to the PERG, and presumes that readers already have basic understanding and skills in clinical electrophysiology. Although much of this document will apply equally to adults and children, the standard is not necessarily appropriate to paediatric applications. The standard will be reviewed by ISCEV every four years.