Flash photolysis of vertebrate photoreceptors

We consider the flash photolysis of visual pigment in a layered array of absorbers as in a vertebrate photoreceptor. The absorbers can be in three states, corresponding to the original product, an intermediate state and the final product. We include in our analysis photoreversal and transition quantum efficiency. We derive expressions for each layer and for the receptor as a whole, of photon incidence and absorption probabilities and of pigment bleaching. Our theoretical expressions agree under suitable conditions with equations derived by others on an empirical basis; and our computed results are in satisfactory agreement with experimental data. Our model should therefore prove useful in analyzing photolysis under physiological conditions.