Abstract
Purpose :
Recent studies (Abed et al, Clin Exp Ophthalmol, 2018).have shown that the photopic negative response (PhNR) of the cone-mediated electroretinogram (ERG) can be altered in early stages of Stargardt’s disease (STGD), related to ABCA4 gene mutations. In many STGD patients, PhNR losses may even precede or can be larger than b-wave losses. Pathophysiological similarities shared by STGD and age-related macular degeneration (AMD), prompted us to investigate whether, and to what extent, PhNR and cone-mediated b-wave are altered in AMD patients.
Methods :
Cone-mediated ERG to single flash stimuli (2 cd/m2 over a 20 cd/m2 background) were recorded in 30 patients with intermediate AMD ( in at least one eye, determined by a masked observer according to the classification by Ferris et al, Ophthalmology, 2013).Sixty advanced AMD, 23 early AMD patients and 17 age-matched normal subjects were also tested. Cone ERG b-waves and PhNR were measured in their amplitudes and implicit times according to a published protocol (Abed et al., 2018)
Results :
Compared to controls, mean PhNR and b-wave amplitudes were reduced (p < 0.01) and their implicit times delayed (p < 0.05) in AMD patients with intermediate and advanced AMD. B-wave, but not PhNR amplitudes, were negatively correlated (p < 0.05) with the AMD stage, showing progressive losses associated with disease severity. Considering both amplitude and implicit time, PhNR and b-wave were altered in 12/30 and 14/30 intermediate AMD patients, respectively.
Conclusions :
Both cone-mediated b-wave and PhNR of the Ganzfeld cone ERG reveals a retina-wide cone dysfunction in AMD. The correlation of b-wave amplitude with AMD stage suggests the potential use of Ganzfeld cone ERG for functional assessment and follow-up of intermediate AMD.
This is a 2020 ARVO Annual Meeting abstract.