The human S-cone electroretinogram and its variation among subjects with and without L and M-cone function.

PURPOSE To examine the S-cone ERG in subjects with and without L and M-cone function. METHODS Ganzfeld spectral flashes in the presence of strong Ganzfeld adapting fields are used to elicit S-cone ERGs. RESULTS The S-cone ERG b-wave ranges from 0.2 to 4 mV in amplitude and 38-45 msec in implicit time. There is a progressive decrease in amplitude with age. The response is similar in subjects with or without L and M cone function. CONCLUSION The S-cone ERG is detectable in subjects of all ages, but intersubject variability limits its diagnostic usefulness. The S-cone ERG is slightly later than but does not appear to be obviously influenced by the L and M-cone ERG.