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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.
© Copyright 2025 Coding Ahead. All rights reserved.
The multifocal electroretinography (mfERG) procedure is indicated for the evaluation of various retinal conditions and disorders. The following are the specific indications for performing mfERG:
The multifocal electroretinography (mfERG) procedure involves several critical steps to ensure accurate measurement of retinal responses. The first step is the instillation of mydriatic drops into the patient's eyes to dilate the pupils, which is essential for maximizing light exposure during the test. Following this, the patient undergoes a period of adaptation, either in darkness or under light, for several minutes, depending on the specific protocol being utilized. This adaptation phase is crucial for preparing the retina to respond effectively to the light stimuli that will be presented during the test.
Once the adaptation is complete, electrodes are placed on the surface of the eye. This is done under dim red illumination to prevent interference with the light stimuli. The electrodes can be of various types, including contact lens electrodes that rest directly on the cornea or gold Mylar tape electrodes that are positioned between the lower eyelid and the sclera or cornea. These electrodes are then connected to a recording device that will capture the electrical responses generated by the retina.
To maintain stability during the procedure, the patient's head is supported using head and chin rests. The mfERG test is initiated by stimulating the eye with a series of light flashes produced by a bright light source, which may include LEDs, a strobe lamp, or a full-field dome with its own light source. The light flashes are presented in a specific sequence, and the electrical responses from the retina are recorded first in a dark environment and then with background lighting. This dual recording allows for a comprehensive assessment of retinal function under varying conditions.
The electrical responses elicited by the light stimuli are captured by the electrodes and represented digitally as waveforms. In mfERG, multiple areas of the retina are stimulated simultaneously, allowing for the recording of electrical responses from different regions at the same time. This is in contrast to conventional full-field ERG, which records the overall response from the entire retina. After the completion of the test, the recorded waveforms are analyzed, focusing on two primary components: 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 detailed written interpretation of the findings is then provided to assist healthcare professionals in making informed clinical decisions.
After the multifocal electroretinography (mfERG) procedure, patients may experience temporary visual disturbances due to the mydriatic drops used to dilate the pupils. It is generally recommended that patients avoid driving or engaging in activities that require clear vision until the effects of the drops have worn off. The results of the mfERG test are typically analyzed and interpreted by a qualified healthcare professional, who will provide a written report detailing the findings. This report will include an assessment of the a-wave and b-wave components, which are critical for evaluating the health of the retina. Follow-up appointments may be scheduled to discuss the results and any necessary further evaluations or treatments based on the findings of the mfERG.
| Short Descr | MULTIFOCAL ERG W/I&R | Medium Descr | MULTIFOCAL ELECTRORETINOGRAPHY W/I&R | Long Descr | Electroretinography (ERG), with interpretation and report; multifocal (mfERG) | Status Code | Active Code | Global Days | XXX - Global Concept Does Not Apply | PC/TC Indicator (26, TC) | 1 - Diagnostic Tests for Radiology Services | Multiple Procedures (51) | 7 - Special payment adjustment rules on the technical component (TC) of multiple diagnostic ophthalmology services apply... | Bilateral Surgery (50) | 2 - 150% payment adjustment does NOT apply. | Physician Supervisions | 09 - Concept does not apply. | Assistant Surgeon (80, 82) | 0 - Payment restriction for assistants at surgery applies to this procedure... | Co-Surgeons (62) | 0 - Co-surgeons not permitted for this procedure. | Team Surgery (66) | 0 - Team surgeons not permitted for this procedure. | Diagnostic Imaging Family | 99 - Concept Does Not Apply | APC Status Indicator | Procedure or Service, Not Discounted when Multiple | Type of Service (TOS) | Q - Vision Items or Services | Berenson-Eggers TOS (BETOS) | none | MUE | 1 |
| 51 | Multiple procedures: when multiple procedures, other than e/m services, physical medicine and rehabilitation services or provision of supplies (eg, vaccines), are performed at the same session by the same individual, the primary procedure or service may be reported as listed. the additional procedure(s) or service(s) may be identified by appending modifier 51 to the additional procedure or service code(s). note: this modifier should not be appended to designated "add-on" codes (see appendix d). | 26 | Professional component: certain procedures are a combination of a physician or other qualified health care professional component and a technical component. when the physician or other qualified health care professional component is reported separately, the service may be identified by adding modifier 26 to the usual procedure number. | 59 | Distinct procedural service: under certain circumstances, it may be necessary to indicate that a procedure or service was distinct or independent from other non-e/m services performed on the same day. modifier 59 is used to identify procedures/services, other than e/m services, that are not normally reported together, but are appropriate under the circumstances. documentation must support a different session, different procedure or surgery, different site or organ system, separate incision/excision, separate lesion, or separate injury (or area of injury in extensive injuries) not ordinarily encountered or performed on the same day by the same individual. however, when another already established modifier is appropriate it should be used rather than modifier 59. only if no more descriptive modifier is available, and the use of modifier 59 best explains the circumstances, should modifier 59 be used. note: modifier 59 should not be appended to an e/m service. to report a separate and distinct e/m service with a non-e/m service performed on the same date, see modifier 25. | 95 | Synchronous telemedicine service rendered via a real-time interactive audio and video telecommunications system: synchronous telemedicine service is defined as a real-time interaction between a physician or other qualified health care professional and a patient who is located at a distant site from the physician or other qualified health care professional. the totality of the communication of information exchanged between the physician or other qualified health care professional and the patient during the course of the synchronous telemedicine service must be of an amount and nature that would be sufficient to meet the key components and/or requirements of the same service when rendered via a face-to-face interaction. modifier 95 may only be appended to the services listed in appendix p. appendix p is the list of cpt codes for services that are typically performed face-to-face, but may be rendered via a real-time (synchronous) interactive audio and video telecommunications system. | CC | Procedure code change (use 'cc' when the procedure code submitted was changed either for administrative reasons or because an incorrect code was filed) | CR | Catastrophe/disaster related | GA | Waiver of liability statement issued as required by payer policy, individual case | GC | This service has been performed in part by a resident under the direction of a teaching physician | GW | Service not related to the hospice patient's terminal condition | GY | Item or service statutorily excluded, does not meet the definition of any medicare benefit or, for non-medicare insurers, is not a contract benefit | GZ | Item or service expected to be denied as not reasonable and necessary | LT | Left side (used to identify procedures performed on the left side of the body) | TC | Technical component; under certain circumstances, a charge may be made for the technical component alone; under those circumstances the technical component charge is identified by adding modifier 'tc' to the usual procedure number; technical component charges are institutional charges and not billed separately by physicians; however, portable x-ray suppliers only bill for technical component and should utilize modifier tc; the charge data from portable x-ray suppliers will then be used to build customary and prevailing profiles | X2 | Continuous/focused services: for reporting services by clinicians whose expertise is needed for the ongoing management of a chronic disease or a condition that needs to be managed and followed with no planned endpoint to the relationship; reporting clinician service examples include but are not limited to: a rheumatologist taking care of the patient's rheumatoid arthritis longitudinally but not providing general primary care services |
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