Prüfung der zentralen Netzhautfunktion mit dem multifokalen Elektroretinogramm vor und nach photodynamischer Therapie

BACKGROUND: Photodynamic therapy (PDT) is applied for certain forms of choroidal neovascular membrane (CNV). The aim of this study was to investigate the effect of PDT on central retinal function as assessed by multifocal electroretinography (ERG).

METHODS: 24 patients (25 eyes) with CNV (>50% classic 12 eyes) or occult (9 eyes) in age related macular degeneration (AMD) and CNV with pathological myopia (4 eyes) were treated by PDT using Verteporfin((R)). Before and a median of 6 weeks after therapy, central retinal function was examined using multifocal ERG (RetiScan, 61 hexagons, first-order response).

RESULTS: In the area of treatment,we found a tendency of the amplitude of the first positive deflection (P1) to decrease and of the implicit time to increase, but both effects were not statistically significant. These alterations were more pronounced in eyes with occult CNV and in myopia-related CNV. Amplitude reduction and implicit time prolongation could also be found in the areas represented by the multifocal ERG but not treated. There was no significant correlation between change in visual acuity after PDT and amplitude of the multifocal ERG.

CONCLUSION: The effects of PDT on retinal function seem to be moderate as assessed by multifocal ERG. An inherent problem of this investigation was the recruitment of nontreated patients as controls. Future goals are investigations of patients with repeated PDT and of long-term alterations in multifocal ERG after PDT.