P 317
Multifocal ERG (MF-ERG) recorded with the SLO in normal subjects
T. Kaupper, T. A. Berninger
Introduction: MF-ERGs were recorded in healthy volunteerÂ’s subdivided in different age groups from 19 to 73 years. The stimulus was projected via the SLO directly on the retina.
Methods: 36 healthy people 19 to 73 years of age were studied. 53 eyes (32 RE and 21 LE) were included in the study. We worked with the multifocal ERG technique, based on a P133 32MB RAM System (with RETISCAN System, software version 3.11.1, Roland Consult, Germany) and a SLO (Rodenstock). The measurement was made with a Jet-electrode at the cornea, the reference electrode was fixed to the temple and the ground electrode to the forehead. For the stimulus we used alternating black and white hexagons (flash, FOK = first order Kernel) of 61 hexagonal area. The viewing angle was 12 degree. We recorded at least 6 cycles per eye. Each cycle was automatically corrected by the Retiscan program, at least about 57 sec. The amplitudes were filtered with 50 and 100 Hz. We excluded persons with refractive errors –3.00 to +3.00 dpt.
Results: The amplitudes and the latencies of the five rings (central to periphery) were analysed. The largest amplitude was observed at the central ring (116.8 +/- 35.2 STD). For the peripheral rings the following values were measured: ring 2: 79.2 +/-18.0 STD; ring 3: 74.1 +/- 17.5 STD; ring 4: 75.9 +/- 20.1 STD; ring 5: 76.7 +/- 21.6 STD). The highest amplitude was found for the age group 40 to 50 years and the lowest by the patients older than 60 years. No age-related differences were observed for the latencies.
Discussion: The advantage of the MF-ERG recorded with the SLO have to be seen in the fact that the fixation of the patients can be controlled and an exact correlation of the hexagon with the retinal area is possible. However, remarkable difference of the amplitudes were found in comparison to the VGA-monitor. The amplitudes were about 8 to 10 times smaller. Also a higher standard deviation was observed, which is to our opinion due to the fact that the laser of the SLO is to easily dejusted. The correction of this systemic error will help to increase the value of the combination SLO and MF-ERG.
The study was supported by Chibret, Germany
University Eye Hospital, Munich, Mathildenstr. 8, 80336 Munich