Fig. 3.

Rhodopsin bleach dependence and kinetics of rod elongation and backscattering increases. Results were obtained with the experimental paradigm of Fig. 1, using both albino (BALB/c) mice (A and B) and pigmented (C57Bl6/J) mice (C and D) with light exposures that bleached between 0.04% and 95% of the rhodopsin (symbol key in A). E and F plot the dependence of the amplitudes of the elongation (E) and IS/OS backscatter increases as a function of the bleach level. The smooth curve in E is an exponential function that reaches 1-e⁻¹ of the saturated level at a 2.6% level of bleaching; the smooth curves in F are quadratic functions that serve to highlight the declining rate of backscatter increase with increasing bleach level. In A–D the symbols plot mean values, and the colored backgrounds plot the SEMs of the traces. Each trace is the average of at least 6 experiments from both eyes of at least three mice. For the lower bleach levels up to 44 individual experiments were averaged. (OCT data collection was truncated short of 300 s in the experiments with the three lowest bleach levels.) The fraction bleached can be converted into photoisomerizations per rod (R*) by multiplying by 7 × 10⁷, the average number of rhodopsin molecules per mouse rod (81).