Fig. 6.
Rod plateaux after partial bleaches. Thresholds to 500-nm stimuli at 12 deg inferior field following various flash bleaches are shown for a normal subject (A), the heterozygote (B), and the homozygote (C). Gray parallel lines are simultaneously fit to the log–linear recovery portions of the partial bleaches and the full bleach data shown in Fig. 4. In the homozygote (C), gray diagonal lines are extended with horizontal lines corresponding to the plateau regions (a–d). Kinetics of the early rapid rod sensitivity recovery following 0.5%, 2%, and 3.5% bleaches in the homozygote are compared to the 99% cone recovery in the homozygote (squares with cross) and the 0.5% rod recovery of the normal (D). All curves are vertically shifted to match thresholds at 20 min. Thresholds obtained with different wavelength stimuli dark-adapted (DA) during the cone plateau (CP) following a full bleach in the normal, heterozygote, and homozygote are compared to thresholds during rod plateaux (a–d) following partial bleaches in the homozygote (E). Scotopic luminous efficiency function (solid lines) and the peripheral cone spectral-sensitivity function (dashed lines) are fit to the available thresholds. Rod plateau thresholds of the homozygote plotted against fraction of bleach (F).