Electroretinograms and Visual Evoked Potentials Elicited by Spectral Stimuli in a Patient With Enhanced S-Cone Syndrome

Abstract

Purpose: To evaluate the properties of the retina of a Japanese patient with enhanced S-cone syndrome by analyzing electroretinograms (ERGs) and visual evoked potentials (VEPs) elicited by different spectral stimuli. Methods: Ganzfeld spectral flashes in the presence of strong white adapting background illumination were used to elicit cone ERGs and VEPs. Results: The cone ERG elicited in the patient by short wavelength stimuli was distinctly different from the normal S-cone ERG. The action spectrum of the cone ERG confirmed its relative hypersensitivity to short wavelengths. The action spectrum of the VEP for the patient showed a similar relative hypersensitivity to short wavelengths. The response of the VEPs to short wavelength stimuli was different in waveform from the VEP response to longer wavelength stimuli observed in a normal subject. Conclusions: These results indicate that the hypersensitivity to short wavelengths is transmitted to the central nervous system and that there is a short wavelength transducing photopigment in many of the photoreceptors, either abnormal S-cones or photopic rods.