Multifocal Electroretinogram with a Multiflash Stimulation Technique in Open-Angle Glaucoma

Abstract

Purpose: To analyze a multiflash multifocal electroretinogram in 20 patients with open-angle glaucoma (OAG). Methods: The stimulation sequence consisted of a binary m-sequence (L_max 200 cd/m², L_min <1 cd/m²). Each m-sequence stimulus was followed by three global flashes (luminance: 400 cd/m²) at an interval of 26 ms. Results: The presence of a response to the three global flashes indicated an adaptive effect of the response to the preceding m-sequence stimulus. In the nasal retinal response average the relative amplitude contribution of the response to the second global flash in relation to the other two global flash responses was outside the range of normal (10th–90th percentile) in 10 of 20 OAG patients. Conclusions: The changes in the relative contribution of the response to the second global flash seem indicative of impaired adaptive effects presumably due to inner retinal damage.

The Clinical Applications of Multifocal Electroretinography: A Systematic Review

“…279 This stimulus results in a direct response due to focal flash and an induced response due to interaction of focal and global flash and was proposed to enhance responses from the ganglion cell and the optic nerve head component (ONHC). 63,222,282 It was shown that diabetic patients without retinopathy had significantly lower amplitude in the induced component, whereas the direct response was similar compared with controls without diabetes. 281 The application of this multifocal stimulus with periodic global flash may enable early detection of retinal dysfunction in diabetic patients.…”

“…63,222,289 Techniques which have been employed to enhance these components included insertions of three successive global flashes or alternating dark and global flashes in between the multifocal stimuli. 63,222,281 Palmowski et al demonstrated that patients with POAG had reduction in the nasal retinal response amplitude to the second of the three global flashes compared with control. 222 The clinical application, however, is limited because many of the POAG patients still had amplitudes within normal limits.…”

“…63,222,281 Palmowski et al demonstrated that patients with POAG had reduction in the nasal retinal response amplitude to the second of the three global flashes compared with control. 222 The clinical application, however, is limited because many of the POAG patients still had amplitudes within normal limits. Fortune et al also showed that glaucoma patients had less asymmetry between nasal and temporal responses due to reduction of the oscillatory component of the induced response in the temporal retina.…”

The 2-global flash mfERG in glaucoma: attempting to increase sensitivity by reducing the focal flash luminance and changing filter settings

“…Previous findings showed that interposing bright global flashes into the stimulation sequence increased the inner retinal contributions to the mfERG and therefore its sensitivity in glaucoma. With the use of 3 global flashes, the sensitivity to detect glaucomatous dysfunction was 50 % [10]. One single global flash increased the sensitivity to 75 % and the specificity to 83 %.…”

“…Previous studies found significant differences between glaucoma and control when the bandpass filter was set at 10-300 Hz [7]. Applying the same filter setting, the sensitivity of the mfERG to detect glaucomatous retinal dysfunction was increased when global flash paradigms were introduced [10,11].…”