Electroretinography (ERG)

Jurisdiction: J15 MAC Part B. States: Kentucky, Ohio. Type: Active LCD

Electroretinography (ERG) is considered reasonable and medically necessary for: Detection of loss of retinal function, OR To distinguish retinal from optic nerve lesions, OR Detecting chloroquine and hydroxychloroquine toxicity ERG is investigational for all other indications, including glaucoma. Background: The full-field electroretinogram (ERG) is used to detect loss of retinal function or distinguish between retinal and optic nerve lesions. ERG measures the electrical activity generated by neural and non-neuronal cells in the retina in response to a light stimulus. ERGs are usually obtained using electrodes embedded in a corneal contact lens or a thin wire inside the lower eyelid, which measures a summation of retinal electrical activity at the corneal surface. The ERG provides information about the macula, composed mainly of cones and used for primary central and color vision, and the rest of the retina is mainly composed of rod photoreceptors, used in peripheral and night (scotopic) vision. By providing information about the rods and cones, ERG helps distinguish retinal degeneration and dystrophies. 1 The International Society for Clinical Electrophysiology of Vision (ISCEV) introduced minimum ERG standards in 1989. The ERG helps to distinguish retinal degeneration and dystrophies. 2 The widespread use of electrophysiological measurements has been hindered by limitations associated with its widespread clinical implication and large magnitude of measurement variability. 3 Definitions: Full-Field ERG (ffERG)- measures mass response for the retina in response to flashing lights and is valuable for conditions with widespread retinal dysfunction but not useful for small retinal lesions. 4 Focal ERG (fERG)- also called foveal ERG, measures the functional integrity of the central macula. 4 Multifocal ERG (mfERG)- higher resolution form of ERG, enabling assessment of ERG activity in small areas of the retina by measuring local ERG responses and providing spatial information. It measures the photoreceptors and aids in the detection of localized abnormalities within the macula. 2,4 Pattern electroretinography (PERG) (also called reversal pattern ERG) uses pattern-reversal stimuli to elicit electrical activity in the retina and monitor retinal ganglion cell activity, and used to detect subtle optic neuropathies. 2,5 Photopic Negative Response ERG (PhNR) is a slow ERG wave recorded under photopic conditions and accesses ganglion cells on cones and bipolar cells. 6