The electroretinographic characteristics of congenital tritan defects.

Electroretinographic studies were performed in three congenital tritanopic subjects in a single pedigree. The b-waves were recorded in the presence of white and intense yellow adaptation in response to 16 monochromatic light stimuli. Compared with the response of normal subjects, a marked reduction or a lack of the blue cone responses was clearly shown in the spectral response patterns of tritanopes. Electroretinograms elicited by strong white stimulation or xenon flashes showed negative responses (a-waves larger than b-waves) with normal rod function in each tritanopic subject. This finding points to abnormalities of red cone and green cone function as well in tritanopes.