Electroretinograms and visual evoked potentials elicited by spectral stimuli in a patient with enhanced S-cone syndrome.

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.