CPT® Code 92273

Electroretinography (ERG) is a diagnostic procedure utilized to assess and evaluate the functionality of the retina and optic nerve by measuring the electrical responses generated by retinal cells when exposed to light stimuli. This test is particularly important for diagnosing various retinal conditions and understanding the overall health of the retina. Prior to the procedure, mydriatic drops are administered to dilate the pupil, which enhances the visibility of the retina 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 procedure, electrodes are carefully placed on the surface of the eye under dim red light to minimize any interference with the test results. 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 activity of the retina. To ensure stability during the test, the patient's head is supported using head and chin rests. The retina is stimulated by a series of light flashes emitted from a bright light source, which may include LEDs, a strobe lamp, or a full-field dome equipped with its own illumination. The electrical responses elicited by these light flashes are recorded first in a dark environment and subsequently with background lighting. The resulting electrical activity is captured by the electrodes and represented digitally as a waveform. In the case of conventional full field or flash ERG, specifically identified by CPT® code 92273, 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 responses. 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 completion of the ERG test, two primary components are typically analyzed: the a-wave, which reflects the health of the photoreceptors in the outer retina, and the b-wave, which indicates the health of the inner layers of the retina. A comprehensive written interpretation of the findings is subsequently provided to assist in clinical decision-making.