The Stiles-Crawford effect in the eye of the blowfly, Calliphora erythrocephala

Stiles-Crawford-like effects (that is, directional sensitivity of the retina) were investigated in the fly's eye. Intracellular recordings from the visual sense cells were made, and the radiation patterns emerging from the photoreceptors with antidromic light were photographed, and evaluated with a microdensitometer. The measurements from both methods agree well, and can be satisfactorily described by a theoretical model based on waveguide theory. Clear radiation patterns from the first and second order modes were observed at the level of the cornea. As in the vertebrate eye, the photoreceptors are aligned towards the center of the lens, a phenomenon for which a theoretical explanation is proposed.