Microcomputer analyses of clinical ERG, EOG, and other tests of retinal function

The electroretinogram (ERG) and electro-oculogram (EOG) are two of the most frequently used visual electrodiagnostic tests of retinal function. The ERG and EOG are easily measured, but there are many engineering difficulties in processing their signal data because the response amplitudes are relatively small, and the relevant signals are buried in electromagnetic and biologic noise. These tests tend to be time consuming, so they lend themselves to automatic control. This article describes the engineering designs relative to a microprocessor-based electrophysiologic laboratory at Emory University Clinic to perform ERG, EOG, and other clinical tests of retinal function. A comparable system that offered both the ability to accept data from a variety of transducers and the flexibility to permit all of the planned testing protocols was not available from any commercial source.