Figure 3.

Dark-adapted (scotopic) ERGs from a 7-week-old normal mixed-breed kitten showing responses to three different light intensities: 300, 1000, and 3000 mcd · s/m². Similar recordings are shown for an Rdy-affected littermate at ages 7 and 11 weeks, obtained with identical procedures as for the normal kitten. Note the initial recordable ERG in the affected kitten at 7 weeks, with clear a- and b-wave recordings, both of low amplitude and increased implicit time. Within 4 weeks a- and b-waves from the same kitten were nonrecordable and were replaced by a late-onset negative waveform. Amplitude and implicit time calibrations are shown on the ordinate in microvolts and on the abscissa in milliseconds. Note that the amplitude calibration varies in the ordinate for most of the recordings.