CPT® Code 92274

Electroretinography (ERG) is a diagnostic procedure utilized to assess and evaluate various conditions that may affect the retina and optic nerve. This test measures the electrical activity generated by retinal cells in response to light stimuli, providing valuable insights into the functional status of the retina. The procedure typically begins with the administration of mydriatic drops to dilate the pupil, which is essential for optimal light exposure during testing. Depending on the specific protocol being followed, the patient may undergo a period of dark or light adaptation lasting several minutes to prepare the retina for accurate measurement. During the test, electrodes are strategically placed on the surface of the eye under dim red illumination to minimize interference with the light stimulus. Various types of electrodes can be employed, including contact lens electrodes that rest directly on the cornea or gold Mylar tape electrodes positioned between the lower eyelid and the sclera or cornea. These electrodes are then connected to a recording device that captures the electrical responses elicited by light stimuli. To ensure stability during the procedure, the patient's head is supported using head and chin rests. The eye is subjected to a series of light flashes generated by a bright light source, which may include LEDs, a strobe lamp, or a full-field dome equipped with its own illumination. The responses to these light flashes are recorded first in a dark environment and subsequently with background lighting. The electrical responses from the retina, triggered by the light flashes, are captured by the electrodes and digitally represented as waveforms. In the context of conventional full-field or flash ERG, the test evokes a summation of the electrical responses from the entire retina using a Ganzfeld stimulus, which scatters light throughout the eye. While this method effectively records the overall retinal response, it does not provide localized information. In contrast, multifocal ERG (mfERG) stimulates multiple areas of the retina simultaneously, allowing for the recording of electrical responses from different retinal regions at the same time. After the test is completed, two primary components—the a-wave and b-wave—are evaluated, which correspond to the health of the outer photoreceptors and the inner layers of the retina, respectively. A comprehensive written interpretation of the findings is subsequently provided to assist in clinical decision-making.