The Electroretinogram

The Electroretinogram (ERG) (CPT 95930)

This is an objective test somewhat similar to the VEP but test RETINA function not OPTIC NERVE function. A contact lens is placed in each eye and the response to a flash of light is recorded as the electrical activity of the retina (recorded by electrodes placed in the face/head). This is a test not use in patients known to have MS but in patients whose visual loss’ cause  is not known to see if the visual loss is of retinal origin.