An updated standard for clinical electroretinography.

The value of the electroretinogram (ERG) in clinical practice depends in part on its consistency and the ability to compare results with other laboratories and the literature. These issues were addressed by the publication of the International Standard for Clinical Electroretinography in 1989. This Standard provided technical information and defined a core of basic test procedures and test responses (Figure) to ensure that ERGs performed worldwide would be equivalent for clinical and research purposes. Most major laboratories now subscribe to the tenets of the Standard, and it should be noted that the Standard does not limit laboratories from doing additional specialized tests (beyond the recommendations) for either clinical purposes or research. Since science and medicine are not static, the original Standard mandated revision every 4 years by the International Society for Clinical Electrophysiology of Vision. The first revision, titled "Standard for Clinical Electrophysiology (1994 Update)," has just been published, and it contains changes and new provisions that should be reviewed carefully by those who perform ERGs. The major changes and additions in the updated ERG Standard are as follows.