Introduction

Full-field electroretinography (ERG) is a widely used ocular electrophysiologic test. In 1989 a basic protocol was standardized so that ERGs could be recorded comparably throughout the world¹. This standard was updated most recently in 1999². Standards for five commonly obtained ERGs were presented:

This document is an updated version of the standard. There are no major changes in the basic ERGs, but readers should note the intensity range of the “standard flash (SF)” which had been printed differently in the 1999 version. An additional dark-adapted ERG to a higher-intensity stimulus is also suggested to users, as it is now being used widely and has diagnostic value. However, it has not yet been characterized sufficiently to be considered a required part of the standard. Because the stimulus for this additional ERG is brighter than the SF, we no longer use the term “maximal” for the dark-adapted ERG to a SF.

This standard is intended as a guide to practice and to assist in interpretation of ERGs. The five basic ERGs represent the minimum of what an ERG evaluation should include. The standard describes simple technical procedures that allow reproducible ERGs to be recorded under a few defined conditions, from patients of all ages (including infants). Different procedures can provide equivalent ERGs. 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 standard ERGs be used widely, but not to the exclusion of other ERGs or additional tests that individual laboratories may choose or continue to use. There are also specialized types of ERG, which may provide additional information about retinal function (see table 20.3.1), that are not covered by this standard. We encourage electrophysiologists to learn about and try expanded test protocols and newer tests to maximize the diagnostic value of the ERG for their patients. ISCEV guidelines for the calibration of electrophysiologic equipment³, guidelines for recording the multifocal ERG⁴, and standards for the pattern ERG⁵, electro-oculogram⁶ and visual evoked potentials⁷ have also been published.

Because of the rapid rate of change of ERG techniques, this standard will be reviewed every four years. We have made recommendations that commercial recording equipment should have the capability to record ERGs under conditions that are outside the present standard but that are nevertheless either widely used or likely to be needed in the future. Note that this document is not a safety standard, and does not mandate particular procedures for individual patients.

The organization of this report is as follows: