ISCEV guidelines for clinical multifocal electroretinography (2007 edition)

Abstract

The clinical multifocal electroretinogram (mfERG) is an electrophysiological test of local retinal function. With this technique, many local ERG responses, typically 61 or 103, are recorded from the cone-driven retina under light-adapted conditions. This document specifies guidelines for performance of the test. It also provides detailed guidance on technical and practical issues, as well as on reporting test results. The main objective of the guidelines is to promote consistent quality of mfERG testing and reporting within and among centers. These 2007 guidelines, from the International Society for Clinical Electrophysiology of Vision (ISCEV: http://www.iscev.org ), replace the ISCEV guidelines for the mfERG published in 2003.

Fig. 1

(a) Representative hexagonal mfERG stimulus array with 61 elements scaled with eccentricity. Roughly half of the elements are illuminated at any one time. (b) Same as in panel A for an array with 103 elements

Fig. 2

Diagram of an mfERG response to show the designation of the major features of the waveform

Fig. 3

Sample mfERG trace arrays (field view) with 61 elements (panel a) and 103 elements (panel b). (c, d) The 3-D response density plots (field view) associated with panels a and b

Fig. 4

The mfERG trace array (left panel, field view) and the probability plot from standard automated perimetry (right panel) for a patient with retinitis pigmentosa. The contours for a radius of 5 and 15° are shown. The light gray, dark gray, and black squares indicate statistically significant field loss at the 5, 1 and 0.5 percent levels, respectively

Fig. 5

The mfERG responses in Fig. 3b were grouped by concentric rings and summed to yield the ‘Summed’ responses in panel c. These summed responses are divided by the area of the elements of the ring for the ‘Response Density’ responses (panel a) and normalized so each has the same amplitude for the ‘Normalized’ responses (panel b)

Fig. A1

Electrical noise. The trace array shows 60 Hz signals contaminating the responses

Fig. A2

Eccentric fixation. The subject with normal vision fixated at the + instead of at the center. As a result, the calculated response magnitudes are altered, and there is a false appearance of central retinal dysfunction

Fig. A3

Shadowing error. The subject’s view was obscured on one side by the edge of a refracting lens. As a result, both the trace array and 3-D plot show a false reduction in amplitude on one side

Fig. A4

Weak signals and erroneous central peak. These recordings were obtained from a contact lens electrode placed in a beaker of water. Therefore, there are no mfERG responses in these records. However, the 3-D plot shows a central peak because the noise level is divided by the stimulus area