Electrophysiological signs of retinal cone remodeling in geographic atrophy of the pigment epithelium in patients with non-exudative age-related macular degeneration

Abstract

Testing patients with primary geographic atrophy (GA) requires a multimodal approach and identification of functional biomarkers characterizing retinal structural remodeling.Purpose: to identify the changes in the functional activity of the retinal cone system, which may serve as biomarkers of primary GA in non-exudative age-related macular degeneration (AMD).Material and methods. We tested 22 patients (30 eyes) aged 45–83 (ave. 72.1 ± 10.8 years) with non-exudative AMD and 18 age matched controls (60.2 ± 7.6 years) all of which underwent standard ophthalmological examinations, optical coherence tomography, autofluorescence study, and fundus photography. Standard photopic ERGs, photopic flicker ERGs to stimuli with frequencies of 8.3, 10, 12, and 24 Hz, multifocal ERG (mfERG), and electrooculogram (EOG) were recorded.Results. Electroretinographic signs for GA of retinal pigment epithelium and choriocapillary layer atrophy were described. The results confirm early impairment of the activity of cones in GA and weakening of the functional interaction of M ller cells with the cone bipolar cells. The delayed P1 peak latency of mfERG indicates a decrease in the entire central retina function in non-exudative AMD. A selective reduction in the fovea's mfERG magnitude can serve as a biomarker of primary GA. The spread of the P1 anomaly to adjacent rings may indicate a possible risk of disease progression. A decrease in the dark trough on the EOG and an increase in the Arden ratio can serve as a biomarker of primary GA.Conclusion. We determined electrophysiological signs which can serve as markers of early retinal dysfunction in eyes with primary GA and non-exudative AMD.