Comparison of different high resolution multifocal electroretinogram recordings in patients with age-related maculopathy

AIM: to compare two different resolutions of multifocal electroretinogram recordings (MF-ERG) in patients with age-related macular degeneration (AMD). PATIENTS AND METHODS: in 20 eyes (14 patients) with early or late stages of AMD, MF-ERGs of 8 min duration were recorded using a low and a high resolution. The central 50 degrees of the retina were stimulated by 103 as well as by 241 stimulus elements. Results were compared with one another and with an age-matched control group. RESULTS: when response averages of equal eccentricity were analysed, amplitudes of the MF-ERG differed significantly from normal within the central 40 degrees. This held true for both low (103) and high (241) resolutions. Sixteen of 20 eyes also showed focal retinal dysfunction at both resolutions. In one case, the high resolution MF-ERGs could detect functional deficits that could not be seen with the lower resolution. However, due to a reduced signal-to-noise ratio three high resolution recordings could not be analysed. CONCLUSION: high resolution MF-ERG seems more sensitive than low resolution MF-ERG. However, the low resolution (103) MF-ERG is recommended for routine application in the clinic because of its better signal-to-noise ratio.