Analysis of individual cone-photoreceptor directionality using scanning laser ophthalmoscopy

Scanning laser ophthalmoscopy has been used to measure individual cone-photoreceptor directionalities in the living human eye. The directionality is determined at different retinal eccentricities where it is expected that cones have diameters ranging between 5-10μm, comparable to the spot size of the incident beam. Individual cone directionality values are compared with the predicted directionalities obtained by using the waveguide model of light coupling to and from photoreceptors for the case of a focused incident beam.