Purpose:
While the morphologic substrate of subretinal drusenoid deposits (SDD) is still unknown, different studies were able to demonstrate a strong relationship to late stage age-related macular degeneration (AMD) and AMD progression. However, the functional relevance of SDD remains unclear. Multifocal electroretinogram (mfERG) allows for measurement of local ERG activity from the cone-driven retina and provides a topographic map of retinal electrophysiological activity.
Methods:
16 eyes of 12 patients with SDD in the posterior pole and no other phenotypic retinal alteration such as conventional drusen, choroidal neovascularization (CNV), geographic atrophy (GA) were included (5 females, 11 males; age 77.7 ± 4.4 years). Patients underwent fundus photography, spectral domain optical coherence tomography (SD-OCT), fluorescence angiography (FA) and confocal scanning laser ophthalmoscopy (cSLO) (Autofluorescence [ = 830 nm], near-infrared reflectance [ = 830 nm)]) (Spectralis, Heidelberg Engineering, Germany). mfERG measurements (RetiPort, Roland Consult, Germany) were performed according to latest ISCEV guidelines.
Results:
In 4 patients exclusively SDD were present in both eyes. In 8 patients exclusively SDD were present in one eye, in the fellow eye 7 showed a CNV and 1 showed an area of GA. In all included eyes SDD could be demonstrated in SD-OCT, FA and cSLO corresponding to previous publications. By mfERG measurements, we were not able to identify any significant decrease in retinal response in the areas where SDD were present compared to non-affected areas. However, a local or general decrease of retinal mfERG response independent of SDD localization was found in 4 out of 16 eyes.
Conclusions:
SDD represent a common phenotypic hallmark in eyes with AMD. Contrary to other phenotypic characteristics of AMD, mfERG measurements did not show definite interference of electro¬physiological activity in retinal areas exclusively affected with SDD. Follow-up measurements as well as a larger patient collective are required before drawing definite conclusions concerning the functional relevance of SDD.
Keywords: age-related macular degeneration • drusen • electroretinography: clinical