Abstract
Purpose::
Multifocal electroretinogram (mfERG) has been proven useful in the assessment of macular function. Nevertheless mfERG results are altered in patients with instable or excentric fixation. Recently a new mfERG system has been introduced, enabling a fundus controlled mfERG by simultaneously monitoring eye movements with the use of a digital fundus camera. Aim of this study was to compare mfERG results obtained with the fundus camera with those of the standard CRT screen stimulation.
Methods::
10 eyes of 10 patients with different macular diseases were examined consecutively using the RETISCAN system (Roland Consult, Germany) with standard monitor stimulation (CRT screen) as well as with fundus controlled stimulation (VISUCAM, Zeiss Inc.). mfERG results were compared concerning P1-amplitudes and implicit times as well as the location of the blind spot signal was evaluated.
Results::
In all patients mfERG results were comparable between both methods. Fixation showed to be sufficiently stable in all patients with a central foveal signal. For fundus controlled mfERG a 19 hexagon pattern proved to be reasonable and at least 4 cycles had to be completed to obtain comparable results to those of monitor stimulation. Artifacts caused by fixation instability could be detected easily and in this case examination cycles were repeated for averaging.
Conclusions::
The mfERG RETIscan with VISUCAM seems to be a useful instrument to simultaneously monitor eye movements during a mfERG examination and to correlate mfERG signals to retinal pathology. The distribution and configuration of mfERG amplitudes with the VISUCAM was comparable to those of the CRT screen stimulation. Further studies are needed to evaluate if fundus controlled mfERG improves mfERG reliability.
Keywords: electroretinography: clinical • eye movements: recording techniques • retina