Decreased light- and dark-adapted electroretinogram amplitude (Human Phenotype Ontology id HP_0000654) is decreased amplitude of eletrical response upon electroretinography. Also known as: Decreased ERG amplitude, Decreased amplitudes on flash visual electroretinogram, Decreased electroretinogram, Decreased electroretinogram amplitude, Decreased electroretinogram response, Flattened or absent electroretinogram, Reduced ERG, Reduced electroretinogram.