Concurrent birefringence and forward light-scattering measurements of flash-bleached rod outer segments

A microretardometer--nephelometer was constructed to measure birefringence and forward-direction light scattering concurrently in single retinal rod outer segments (ROS). The relative contributions of light-induced birefringence and light-scattering changes to observed far-red transmission changes measured normal to the cell axis were evaluated in isolated, whole, flash-bleached ROS. No light-scattering transients were found corresponding to the previously reported rapid birefringence loss associated with the metarhodopsin I lead to metarhodopsin II reaction even under conditions in which such a light-scattering change has been reported for outer-segment fragments.